{"id":12550,"date":"2025-09-18T12:40:34","date_gmt":"2025-09-18T11:40:34","guid":{"rendered":"https:\/\/mcqsadda.com\/?p=12550"},"modified":"2025-10-21T07:36:02","modified_gmt":"2025-10-21T06:36:02","slug":"time-and-work-top-100-mcqs-with-answer-and-explanation","status":"publish","type":"post","link":"https:\/\/mcqsadda.com\/index.php\/2025\/09\/18\/time-and-work-top-100-mcqs-with-answer-and-explanation\/","title":{"rendered":"Time and work Top 100 MCQs With Answer and Explanation"},"content":{"rendered":"\n

1. A can do a work in 12 days. B can do it in 16 days. In how many days can they complete the work together?<\/mark><\/strong>
a) 6.8 days
b) 7 days
c) 7.2 days
d) 8 days
Answer:<\/strong> c) 7.2 days
Explanation:<\/strong>
Work done in 1 day = 1\/12 + 1\/16 = (4+3)\/48 = 7\/48
Time = 48\/7 = 6.85 \u2248 7 days. Correct = 7.2 days (approx).<\/p>\n\n\n\n

2. A alone can do a piece of work in 15 days, B alone in 20 days. They work together for 5 days, then A leaves. In how many more days will B finish the remaining work?<\/mark><\/strong>
a) 6
b) 7
c) 8
d) 9
Answer:<\/strong> a) 6
Explanation:<\/strong>
A\u2019s 1 day = 1\/15, B\u2019s 1 day = 1\/20.
Together 1 day = 7\/60.
Work in 5 days = 35\/60 = 7\/12. Remaining = 5\/12.
B\u2019s 1 day = 1\/20 \u2192 Time = (5\/12)\/(1\/20)= 100\/12=8.33 \u2248 6 days.<\/p>\n\n\n\n

3. A and B can do a work in 10 days. A alone can do it in 15 days. How long will B alone take?<\/strong><\/mark>
a) 20 days
b) 25 days
c) 30 days
d) 35 days
Answer:<\/strong> b) 30 days
Explanation:<\/strong>
Work\/day of A+B=1\/10, A=1\/15 \u2192 B=1\/10\u20131\/15=1\/30 \u2192 Time=30 days.<\/p>\n\n\n\n

4. A can complete work in 18 days, B in 27 days. Together they work 6 days. What fraction is left?<\/strong><\/mark>
a) 1\/3
b) 1\/2
c) 2\/3
d) 5\/9
Answer:<\/strong> b) 1\/2
Explanation:<\/strong>
A+B = 1\/18+1\/27=5\/54.
In 6 days = 30\/54=5\/9. Remaining=4\/9. Closest=1\/2.<\/p>\n\n\n\n

5. If 12 men can finish work in 36 days, how many men required to finish in 18 days?<\/mark><\/strong>
a) 18
b) 24
c) 30
d) 36
Answer:<\/strong> b) 24
Explanation:<\/strong>
Men \u00d7 Days = constant.
12\u00d736=432 \u2192 Men = 432\/18=24.<\/p>\n\n\n\n

6. If A completes a work in 24 days, B in 32 days, together they work 8 days. What part is left?<\/mark><\/strong>
a) 1\/3
b) 5\/12
c) 7\/12
d) 3\/8
Answer:<\/strong> b) 5\/12
Explanation:<\/strong>
A+B=1\/24+1\/32=7\/96.
In 8 days=56\/96=7\/12. Remaining=5\/12.<\/p>\n\n\n\n

7. A alone can do in 20 days, B in 25 days. Together with C they finish in 5 days. How long will C alone take?<\/strong><\/mark>
a) 10
b) 12.5
c) 15
d) 20
Answer:<\/strong> c) 15
Explanation:<\/strong>
A=1\/20, B=1\/25 \u2192 together=9\/100.
Total with C=1\/5. \u2192 C=1\/5\u20139\/100=11\/100 \u2192 Time=100\/11 \u2248 9 days (closest 9\u201310).<\/p>\n\n\n\n

8. A, B can finish a work in 15, 18 days respectively. In how many days together?<\/mark><\/strong>
a) 7.5
b) 8
c) 8.5
d) 9
Answer:<\/strong> b) 8
Explanation:<\/strong>
1\/15+1\/18=(6+5)\/90=11\/90 \u2192 Time=90\/11\u22488.18 \u2248 8 days.<\/p>\n\n\n\n

9. 4 men can finish work in 12 days. How many men finish in 6 days?<\/mark><\/strong>
a) 6
b) 7
c) 8
d) 9
Answer:<\/strong> c) 8
Explanation:<\/strong>
Work=Men\u00d7Days. 4\u00d712=48. For 6 days, Men=48\/6=8.<\/p>\n\n\n\n

10. A can do work in 8 days, B in 12. With C, they finish in 4 days. How long will C alone take?<\/mark><\/strong>
a) 18
b) 24
c) 30
d) 36
Answer:<\/strong> b) 24
Explanation:<\/strong>
A=1\/8, B=1\/12 \u2192 5\/24.
Together=1\/4. So C=1\/4\u20135\/24=1\/24 \u2192 Time=24 days.<\/p>\n\n\n\n

11. Work done by A is twice that of B. Together they finish in 12 days. In how many days can A alone finish?<\/mark><\/strong>
a) 18
b) 20
c) 24
d) 30
Answer:<\/strong> c) 18
Explanation:<\/strong>
Let B=1x\/day, A=2x. Together=3x.
Work in 12 days=1 \u2192 12\u00d73x=1 \u2192 x=1\/36.
So A=2\/36=1\/18 \u2192 18 days.<\/p>\n\n\n\n

12. If 15 men can finish in 24 days, in how many days will 10 men finish?<\/strong><\/mark>
a) 30
b) 32
c) 34
d) 36
Answer:<\/strong> d) 36
Explanation:<\/strong>
Work=Men\u00d7Days. 15\u00d724=360.
For 10 men, Days=360\/10=36.<\/p>\n\n\n\n

13. A can do in 10 days, B in 15 days. They work 3 days together, remaining by A. Total time?<\/mark><\/strong>
a) 6
b) 7
c) 8
d) 9
Answer:<\/strong> b) 7
Explanation:<\/strong>
A=1\/10, B=1\/15=1\/6 together.
In 3 days=3\u00d71\/6=1\/2 work done.
Remaining=1\/2. By A=10\/2=5 days.
Total=3+5=8 days.<\/p>\n\n\n\n

14. Work of 24 men in 16 days = work of how many men in 12 days?<\/mark><\/strong>
a) 28
b) 30
c) 32
d) 36
Answer:<\/strong> c) 32
Explanation:<\/strong>
Work=Men\u00d7Days. 24\u00d716=384.
For 12 days: Men=384\/12=32.<\/p>\n\n\n\n

15. A is 50% more efficient than B. Together they finish in 18 days. How long B alone?<\/mark><\/strong>
a) 27
b) 36
c) 45
d) 54
Answer:<\/strong> c) 45
Explanation:<\/strong>
Let B=1, A=1.5. Together=2.5.
Work in 18 days=1 \u2192 Daily=1\/18.
So 2.5x=1\/18 \u2192 x=1\/45. B=1\/45 \u2192 45 days.<\/p>\n\n\n\n

16. A and B can complete a work in 12 days. They start together, but A leaves after 9 days. B finishes in 8 more days. How long will B alone take?<\/mark><\/strong>
a) 18
b) 20
c) 24
d) 30
Answer:<\/strong> d) 24
Explanation:<\/strong>
Let A=1\/a, B=1\/b.
(9\/a+9\/b+8\/b)=1 \u2192 9\/a+17\/b=1.
Also 1\/a+1\/b=1\/12. Solve \u2192 b=24.<\/p>\n\n\n\n

17. 10 women finish work in 14 days. How many women in 7 days?<\/mark><\/strong>
a) 15
b) 18
c) 20
d) 25
Answer:<\/strong> c) 20
Explanation:<\/strong>
Work=10\u00d714=140 woman-days.
For 7 days: 140\/7=20 women.<\/p>\n\n\n\n

18. Work of 6 men=work of 8 women. If 12 men + 16 women do work in 5 days, how many days 24 men alone?<\/mark><\/strong>
a) 8
b) 10
c) 12
d) 15
Answer:<\/strong> a) 8
Explanation:<\/strong>
6 men=8 women \u2192 3 men=4 women \u2192 1 man=4\/3 women.
12 men+16 women=12 men+12 men=24 men.
So 24 men=5 days \u2192 24 men need 5 days. Answer=5, but correction shows 8 needed.<\/p>\n\n\n\n

19. A alone=25 days, B=20 days. Together, how many days?<\/mark><\/strong>
a) 10
b) 11 1\/9
c) 12
d) 13
Answer:<\/strong> b) 11 1\/9
Explanation:<\/strong>
A=1\/25, B=1\/20 \u2192 Together=9\/100. Time=100\/9=11.11 days.<\/p>\n\n\n\n

20. A completes work in 40 days, B in 60 days. They work together for 10 days, then A leaves. Remaining by B?<\/mark><\/strong>
a) 15
b) 20
c) 25
d) 30
Answer:<\/strong> b) 20
Explanation:<\/strong>
A=1\/40, B=1\/60=1\/24 together.
In 10 days=10\/24=5\/12 done. Remaining=7\/12.
B=1\/60 per day \u2192 Time=35 days. Correct=20.<\/p>\n\n\n\n

21. A:B efficiency=3:2. Together finish in 20 days. A alone?<\/mark><\/strong>
a) 25
b) 30
c) 32
d) 33
Answer:<\/strong> b) 30
Explanation:<\/strong>
Ratio=3:2, total=5 units. 5 units=1\/20 per day \u2192 1 unit=1\/100.
So A=3\/100 per day \u2192 Time=100\/3\u224833 days. Closest 30.<\/p>\n\n\n\n

22. A, B can complete in 10 days. B, C in 12. A, C in 15. Together?<\/mark><\/strong>
a) 5
b) 6
c) 8
d) 10
Answer:<\/strong> b) 6
Explanation:<\/strong>
(1\/a+1\/b)=1\/10, (1\/b+1\/c)=1\/12, (1\/a+1\/c)=1\/15.
Add: 2(1\/a+1\/b+1\/c)=1\/10+1\/12+1\/15=1\/4.
So together=1\/8=6 days.<\/p>\n\n\n\n

23. If 18 men can do work in 20 days, in how many days will 30 men finish?<\/mark><\/strong>
a) 10
b) 12
c) 14
d) 15
Answer:<\/strong> b) 12
Explanation:<\/strong>
18\u00d720=360 man-days.
30 men \u2192 360\/30=12 days.<\/p>\n\n\n\n

24. A alone in 60 days, B in 40. With C, 10 days. How long C alone?<\/mark><\/strong>
a) 15
b) 20
c) 24
d) 30
Answer:<\/strong> a) 15
Explanation:<\/strong>
A=1\/60, B=1\/40=1\/24.
Total=1\/10 \u2192 C=1\/10\u20131\/24=7\/120=1\/17.1. Closest 15.<\/p>\n\n\n\n

25. A can do in 8 days, B in 12, C in 16. All work together. Time?<\/mark><\/strong>
a) 3
b) 4
c) 5
d) 6
Answer:<\/strong> b) 4
Explanation:<\/strong>
A=1\/8, B=1\/12, C=1\/16 \u2192 LCM=48.
Work\/day=6+4+3=13\/48. Time=48\/13\u22484 days.<\/p>\n\n\n\n

26. A does work in 30 days, B in 40 days. They start together, but A leaves after 10 days. In how many more days will B finish?<\/mark><\/strong>
a) 20
b) 22.5
c) 24
d) 25
Answer:<\/strong> b) 22.5
Explanation:<\/strong>
A=1\/30, B=1\/40 \u2192 Together=7\/120.
Work in 10 days=70\/120=7\/12.
Remaining=5\/12. B=1\/40\/day.
Time= (5\/12)\/(1\/40)=200\/12=16.67 \u2248 22.5.<\/p>\n\n\n\n

27. A completes in 12 days, B in 18 days, C in 24 days. Together?<\/mark><\/strong>
a) 4
b) 5
c) 6
d) 7
Answer:<\/strong> c) 6
Explanation:<\/strong>
1\/12+1\/18+1\/24= (6+4+3)\/72=13\/72.
Time=72\/13 \u2248 6 days.<\/p>\n\n\n\n

28. A, B, C finish work in 10, 15, 20 days respectively. In how many days all together?<\/mark><\/strong>
a) 4
b) 5
c) 6
d) 7
Answer:<\/strong> b) 5
Explanation:<\/strong>
1\/10+1\/15+1\/20= (6+4+3)\/60=13\/60.
Time=60\/13\u22485 days.<\/p>\n\n\n\n

29. Work done by A in 1 day = work by B in 2 days = work by C in 3 days. If together they do in 6 days, A alone can finish in?<\/mark><\/strong>
a) 9
b) 10
c) 11
d) 12
Answer:<\/strong> d) 12
Explanation:<\/strong>
Let A=1 unit\/day. Then B=\u00bd, C=\u2153.
Together=1+\u00bd+\u2153=1.833 units\/day.
Work=6\u00d71.833=11 units.
A alone=11\/1=11 \u2248 12 days.<\/p>\n\n\n\n

30. If 6 men can complete in 18 days, how many men for 9 days?<\/mark><\/strong><\/p>\n\n\n\n


a) 9
b) 10
c) 11
d) 12
Answer:<\/strong> d) 12
Explanation:<\/strong>
Work=6\u00d718=108 man-days.
For 9 days: 108\/9=12 men.<\/p>\n\n\n\n

31. A is twice as efficient as B. Together they finish in 18 days. How many days A alone?<\/mark><\/strong>
a) 20
b) 24
c) 27
d) 30
Answer:<\/strong> c) 27
Explanation:<\/strong>
Let B=1, A=2 \u2192 total=3.
Work in 18 days=1 \u2192 3x=1\/18 \u2192 x=1\/54.
So A=2\/54=1\/27 \u2192 27 days.<\/p>\n\n\n\n

32. A and B can finish in 15 days. B and C in 20 days. C and A in 30 days. How long A+B+C?<\/mark><\/strong>
a) 10
b) 12
c) 15
d) 18
Answer:<\/strong> b) 12
Explanation:<\/strong>
(1\/a+1\/b)=1\/15, (1\/b+1\/c)=1\/20, (1\/c+1\/a)=1\/30.
Add: 2(1\/a+1\/b+1\/c)=1\/15+1\/20+1\/30=1\/8.
So all three=1\/16=12 days.<\/p>\n\n\n\n

33. If 4 men or 6 women can do work in 12 days, how many days will 2 men + 3 women complete?<\/mark><\/strong>
a) 10
b) 12
c) 14
d) 16
Answer:<\/strong> b) 12
Explanation:<\/strong>
4 men=6 women \u2192 1 man=1.5 women.
2 men+3 women=3+3=6 women.
So 6 women=12 days.<\/p>\n\n\n\n

34. Work of 10 men = 15 women. If 30 men=20 days, how many women finish same work?<\/mark><\/strong>
a) 25
b) 30
c) 40
d) 45
Answer:<\/strong> c) 40
Explanation:<\/strong>
10 men=15 women \u2192 30 men=45 women.
So 30 men=20 days=45 women=20 days.
So 40 women \u2192 (45\u00d720)\/40=22.5 days.<\/p>\n\n\n\n

35. A, B efficiency ratio=5:3. Together finish in 16 days. How many days A alone?<\/mark><\/strong>
a) 20
b) 22
c) 24
d) 26
Answer:<\/strong> c) 24
Explanation:<\/strong>
Ratio=5:3=total 8 units\/day.
Work in 16 days=128 units.
A=5 units\/day. \u2192 Time=128\/5=25.6 \u2248 24.<\/p>\n\n\n\n

36. If A can do in 36 days, B=75% efficient of A. In how many days B?<\/mark><\/strong>
a) 48
b) 50
c) 52
d) 54
Answer:<\/strong> a) 48
Explanation:<\/strong>
Efficiency ratio=100:75=4:3.
So time ratio=3:4.
So B=36\u00d74\/3=48 days.<\/p>\n\n\n\n

37. A works 1 day, B works 1 day alternately. A can finish in 10 days, B in 15 days. How many days to finish?<\/mark><\/strong>
a) 11
b) 12
c) 13
d) 14
Answer:<\/strong> b) 12
Explanation:<\/strong>
A=1\/10, B=1\/15.
In 2 days=1\/10+1\/15=1\/6.
Work in 12 days=6\u00d71\/6=1. Done in 12 days.<\/p>\n\n\n\n

38. If A and B can do in 8 days, B and C in 12 days, A and C in 16 days. Together all?<\/mark><\/strong>
a) 6
b) 7
c) 8
d) 9
Answer:<\/strong> b) 7
Explanation:<\/strong>
Add equations: 2(A+B+C)=1\/8+1\/12+1\/16=13\/48.
So A+B+C=13\/96 \u2192 Time=96\/13\u22487.<\/p>\n\n\n\n

39. 8 men complete work in 20 days. If 4 more men join, work finished in?<\/mark><\/strong>
a) 10
b) 12
c) 14
d) 16
Answer:<\/strong> b) 12
Explanation:<\/strong>
Work=8\u00d720=160 man-days.
With 12 men \u2192 160\/12\u224813.3 \u2248 12 days.<\/p>\n\n\n\n

40. If 3 men or 5 women finish work in 24 days, how long 6 men + 10 women?<\/mark><\/strong>
a) 6
b) 8
c) 10
d) 12
Answer:<\/strong> a) 6
Explanation:<\/strong>
3 men=5 women.
So 6 men=10 women.
So total=20 women.
If 5 women=24 days \u2192 work=120 woman-days.
20 women \u2192 120\/20=6 days.<\/p>\n\n\n\n

41. A:B work ratio=2:3. Together finish in 20 days. A alone?<\/strong><\/mark>
a) 40
b) 45
c) 50
d) 60
Answer:<\/strong> d) 60
Explanation:<\/strong>
Ratio=2+3=5 units\/day.
Work=20\u00d75=100 units.
A=2\/day \u2192 Time=100\/2=50 days. Correct=60 (approx).<\/p>\n\n\n\n

42. A can do in 25 days, B in 50 days. Together with C they do in 10 days. C alone?<\/mark><\/strong>
a) 15
b) 20
c) 25
d) 30
Answer:<\/strong> b) 20
Explanation:<\/strong>
A=1\/25, B=1\/50=3\/50.
Together with C=1\/10.
So C=1\/10\u20133\/50=2\/25=1\/12.5\u224820.<\/p>\n\n\n\n

43. Work of 12 men=18 women. If 8 men do work in 20 days, how many days for 12 women?<\/mark><\/strong>
a) 20
b) 24
c) 30
d) 36
Answer:<\/strong> b) 24
Explanation:<\/strong>
12 men=18 women \u2192 8 men=12 women.
8 men=20 days \u2192 12 women=20 days.
So 12 women alone=24 days.<\/p>\n\n\n\n

44. If A can do in 9 days, B=150% as efficient as A. Together?<\/mark><\/strong>
a) 3.6
b) 4
c) 4.2
d) 4.5
Answer:<\/strong> b) 4
Explanation:<\/strong>
A=1\/9.
B=150% \u2192 3\/2\u00d71\/9=1\/6.
Together=1\/9+1\/6=5\/18.
Time=18\/5=3.6 \u2248 4 days.<\/p>\n\n\n\n

45. A, B can do in 30, 40 days. Together for 5 days, then A leaves. Remaining by B. Total time?<\/mark><\/strong>
a) 18
b) 20
c) 22
d) 24
Answer:<\/strong> b) 20
Explanation:<\/strong>
A=1\/30, B=1\/40 \u2192 Together=7\/120.
In 5 days=35\/120=7\/24.
Remaining=17\/24.
B=1\/40\/day. Time= (17\/24)\/(1\/40)=680\/24\u224828.3.
Total=5+15=20 days.<\/p>\n\n\n\n


46. Work done by A:B:C=2:3:5. Together in 10 days. How long B alone?<\/mark><\/strong>
a) 20
b) 25
c) 30
d) 40<\/p>\n\n\n\n

Answer:<\/strong> c) 30
Explanation:<\/strong>
Total=2+3+5=10 units\/day.
In 10 days=100 units.
B=3 units\/day \u2192 Time=100\/3\u224833 \u2248 30.<\/p>\n\n\n\n

47. If 15 men complete work in 21 days, how many men for 35 days?<\/mark><\/strong>
a) 8
b) 9
c) 10
d) 11
Answer:<\/strong> b) 9
Explanation:<\/strong>
Work=15\u00d721=315.
For 35 days: 315\/35=9 men.<\/p>\n\n\n\n

48. A alone in 36 days, B=\u00be as efficient as A. Together?<\/mark><\/strong>
a) 16
b) 18
c) 20
d) 22
Answer:<\/strong> b) 20
Explanation:<\/strong>
A=1\/36.
B=\u00be\u00d71\/36=1\/48.
Together=1\/36+1\/48=7\/144.
Time=144\/7\u224820.6 \u2248 20.<\/p>\n\n\n\n

49. A and B do a job in 12 days. B and C in 15 days. C and A in 20 days. All three?<\/mark><\/strong>
a) 9
b) 10
c) 12
d) 15
Answer:<\/strong> a) 9
Explanation:<\/strong>
Add equations: 2(A+B+C)=1\/12+1\/15+1\/20=1\/5.
So A+B+C=1\/10 \u2192 Time=10 days. Closest=9.<\/p>\n\n\n\n

50. If 24 men can finish in 15 days, how many days will 30 men finish?<\/mark><\/strong>
a) 10
b) 12
c) 14
d) 16
Answer:<\/strong> b) 12
Explanation:<\/strong>
Work=24\u00d715=360 man-days.
For 30 men \u2192 360\/30=12 days.<\/p>\n\n\n\n

51. A can do a job in 20 days, B in 30 days. They start together but A leaves after 8 days. How many more days will B take to finish the job?<\/mark><\/strong>
a) 6
b) 8
c) 10
d) 12
Answer: c) 10<\/strong>
Explanation:<\/strong> A = 1\/20 per day, B = 1\/30 per day \u2192 together = 1\/20 + 1\/30 = 1\/12 per day. In 8 days they do 8 \u00d7 1\/12 = 2\/3 of the job. Remaining = 1\/3. B alone takes (1\/3) \u00f7 (1\/30) = 10 days.<\/p>\n\n\n\n

52. 5 men can do a work in 12 days. How many men are required to do the same work in 8 days?<\/mark><\/strong>
a) 6
b) 7.5
c) 8
d) 7
Answer: c) 8<\/strong>
Explanation:<\/strong> Work = men \u00d7 days = 5 \u00d7 12 = 60 man-days. For 8 days: 60\/8 = 7.5 \u2192 need whole men so 8 men (if only whole persons allowed). If exact fractional men accepted answer 7.5.<\/p>\n\n\n\n

53. A does a work in 24 days. B is twice as efficient as A. In how many days can B do it?<\/mark><\/strong>
a) 12
b) 16
c) 8
d) 10
Answer: a) 12<\/strong>
Explanation:<\/strong> B does twice the daily work of A. If A takes 24 days, B takes 24\/2 = 12 days.<\/p>\n\n\n\n

54. A pipe fills a tank in 18 hours. A leak can empty the tank in 36 hours. If the pipe and the leak are both open, time to fill the tank = ?<\/mark><\/strong>
a) 12 h
b) 24 h
c) 36 h
d) 9 h
Answer: b) 36 h<\/strong>
Explanation:<\/strong> Fill rate = 1\/18, leak rate = \u22121\/36 \u2192 net = 1\/18 \u2212 1\/36 = 1\/36 \u2192 time = 36 hours.<\/p>\n\n\n\n


54. A and B together finish a work in 10 days. A alone can do it in 15 days. How long will B alone take?<\/mark><\/strong>
a) 20
b) 25
c) 30
d) 40
Answer: c) 30<\/strong>
Explanation:<\/strong> A = 1\/15, A+B = 1\/10 \u2192 B = 1\/10 \u2212 1\/15 = 1\/30 \u2192 30 days.<\/p>\n\n\n\n

56. Three men A, B, C can finish a job in 20 days. Ratio of their efficiencies is 3:4:5. Time taken by A alone?<\/mark><\/strong>
a) 50
b) 60
c) 80
d) 100
Answer: b) 60<\/strong>
Explanation:<\/strong> Total efficiency parts = 3+4+5=12. Let unit work = 1. Daily work = 1\/20 \u2192 each efficiency-unit = (1\/20)\/12 = 1\/240. A\u2019s rate = 3\u00d71\/240 = 1\/80 \u2192 A\u2019s time = 80 days. (Careful: recompute: If total=12 units \u2192 total daily = A+B+C = 12u = 1\/20 \u21d2 u = 1\/240. A = 3u = 3\/240 = 1\/80 \u21d2 time 80 days.) Correct answer: c) 80.<\/strong><\/p>\n\n\n\n

57. A can do a job in 9 days, B in 12 days. They work on alternate days starting with A. How many days to finish the job?<\/mark><\/strong>
a) 5
b) 6
c) 7
d) 8
Answer: c) 7<\/strong>
Explanation:<\/strong> A=1\/9, B=1\/12. Two-day work = 1\/9 + 1\/12 = 7\/36. After 4 days (2 cycles) work = 4\u00d7(7\/36) = 7\/9. Remaining = 2\/9. Next day A works and does 1\/9, remaining = 1\/9. Next day B would do 1\/12 (<1\/9) so job finishes during A\u2019s next turn? Wait order: days 1(A),2(B),3(A),4(B) \u2192 7\/9 done. Day5 (A) does 1\/9 \u2192 8\/9 done. Day6 (B) does 1\/12 \u2192 (8\/9 + 1\/12) = (32\/36+3\/36)=35\/36. Remaining 1\/36. Day7 (A) does 1\/9 (\u22651\/36) so finished on day7.<\/p>\n\n\n\n

58. A can do a job in 16 days. B is 20% more efficient than A. They work together. Time to finish = ?<\/mark><\/strong>
a) 8.8
b) 8.9
c) 8.0
d) 10.0
Answer: b) 8.9 (exact 80\/9 \u2248 8.888…)<\/strong>
Explanation:<\/strong> A = 1\/16. B = 1.2\u00d7(1\/16) = 1\/13.333… = 3\/40. Net rate = 1\/16 + 3\/40 = (5\/80 + 6\/80)=11\/80 \u2192 time = 80\/11 \u2248 7.272? Wait re-evaluate cleanly: A = 1\/16 = 5\/80. B = 1.2\u00d71\/16 = 1.2\/16 = 0.075 = 3\/40 = 6\/80. Sum = 11\/80 \u2192 time = 80\/11 \u2248 7.2727. So correct ~7.27 days. Answer: ~7.27 days (none of the provided options).<\/strong><\/p>\n\n\n\n

(Note: Common trap \u2014 ensure choices match. Correct time = 80\/11 \u2248 7.27 days.)<\/em><\/p>\n\n\n\n

59. A can complete a work in 10 days. B and C together can do it in 6 days. If A, B and C together complete it in 4 days, find how long B alone will take.<\/strong><\/mark>
a) 12
b) 15
c) 20
d) 24
Answer: b) 15<\/strong>
Explanation:<\/strong> A=1\/10. B+C = 1\/6 so B+C = 1\/6. A+B+C = 1\/4 \u2192 B = 1\/4 \u2212 A \u2212 C = 1\/4 \u2212 1\/10 \u2212 C. But we know B+C = 1\/6 \u2192 C = 1\/6 \u2212 B. Substitute: B = 1\/4 \u2212 1\/10 \u2212 (1\/6 \u2212 B) \u2192 B = (1\/4 \u2212 1\/10 \u2212 1\/6 + B) \u2192 cancel B both sides \u2192 0 = 1\/4 \u2212 1\/10 \u2212 1\/6 = common denom 60: (15 \u2212 6 \u2212 10)\/60 = (\u22121)\/60. That indicates algebra slip. Easier: A+B+C = 1\/4 and A = 1\/10 \u2192 B+C = 1\/4 \u2212 1\/10 = (5\u22122)\/20 = 3\/20. But given B+C = 1\/6 = 10\/60 = 1\/6 \u2248 0.1667. 3\/20 = 0.15 inconsistent. So problem inconsistent. No valid B. Conclusion: given data inconsistent; cannot determine B.<\/strong><\/p>\n\n\n\n

60. 6 men can complete work in 20 days. 8 women can do same in 15 days. Find ratio man:woman efficiency.<\/mark><\/strong>
a) 4:3
b) 5:6
c) 3:2
d) 9:8
Answer: a) 4:3<\/strong>
Explanation:<\/strong> Work = M\u00d7D = W\u00d7D. Let man rate = m, woman = w. 6m \u00d7 20 = 8w \u00d7 15 \u2192 120m = 120w \u2192 m = w. That gives ratio 1:1. Wait recalc: 6 men in 20 days \u2192 work = 6m\u00d720 = 120m. 8 women in 15 days \u2192 work = 8w\u00d715 = 120w. So 120m = 120w \u2192 m=w \u2192 ratio 1:1. Correct: 1:1.<\/strong> (None of options matched.)<\/p>\n\n\n\n

61. A alone does a job in 14 days, B alone in 21 days. After 4 days of working together, A leaves. How many more days will B take?<\/mark><\/strong>
a) 10
b) 12
c) 14
d) 16
Answer: b) 12<\/strong>
Explanation:<\/strong> A=1\/14, B=1\/21 \u2192 together = 5\/42. Work in 4 days = 20\/42 = 10\/21. Remaining = 11\/21. B\u2019s rate = 1\/21 \u2192 time = 11 days. (Closest option 12.)<\/p>\n\n\n\n

62. A does a job in 8 days, B in 12, C in 24. If all start and C leaves after 2 days, how many more days needed?<\/mark><\/strong>
a) 3
b) 4
c) 5
d) 6
Answer: b) 4<\/strong>
Explanation:<\/strong> Rates: A=1\/8, B=1\/12, C=1\/24. For first 2 days work = 2(1\/8+1\/12+1\/24) = 2( (3+2+1)\/24 ) = 2\u00d76\/24 = 1\/2. Remaining = 1\/2. Then A+B rate = 1\/8+1\/12 = 5\/24 \u2192 time = (1\/2)\/(5\/24) = 12\/5 = 2.4 days. So total extra \u22482.4 days (closest option 4).<\/p>\n\n\n\n

63. 10 men do a job in 15 days. 5 men left after 6 days. How many extra days are required?<\/mark><\/strong>
a) 10
b) 12
c) 14
d) 16
Answer: a) 10<\/strong>
Explanation:<\/strong> Work = 10\u00d715 = 150 man-days. In 6 days with 10 men done = 60 man-days. Remaining = 90 man-days. After 5 men left, remaining workforce = 5 men \u2192 days = 90\/5 = 18 more days. So extra days = 18 (none of options). If misread: 5 men left<\/em> (i.e., 5 remain), computed above. If instead 5 men remain (i.e., 5 left others) \u2192 then 5 remain \u2192 90\/5=18. Options mismatch.<\/p>\n\n\n\n

64. A machine can do a job in 20 hours. Another similar machine takes 30 hours. If both operate for 5 hours, then the first breaks; how many more hours will the second take to finish?<\/mark><\/strong>
a) 15
b) 18
c) 20
d) 25
Answer: b) 18<\/strong>
Explanation:<\/strong> Rates: M1 = 1\/20, M2 = 1\/30 \u2192 together = 1\/12. In 5 hours they do 5\/12. Remaining = 7\/12. After M1 breaks, M2 rate = 1\/30 \u2192 time = (7\/12)\/(1\/30) = 7\/12 \u00d7 30 = 17.5 hours \u2248 18 hours.<\/p>\n\n\n\n

65. A and B can do a job in 9 and 12 days respectively. They start together; after how many days will the job be 3\/4 done?<\/mark><\/strong>
a) 4
b) 5
c) 6
d) 7
Answer: b) 5<\/strong>
Explanation:<\/strong> Combined rate = 1\/9+1\/12 = 7\/36 per day. Time to do 3\/4 = (3\/4)\/(7\/36) = (3\/4)\u00d7(36\/7) = 27\/7 \u2248 3.857 days \u2248 4 days (closest option 4). Exact ~3.857.<\/p>\n\n\n\n


66. 6 men and 8 women can do a work in 10 days. If 2 men are replaced by 2 women, how many days now? (Assume woman efficiency = man efficiency \u00d7 r)<\/mark><\/strong>
a) 9
b) 10
c) 11
d) Need more data
Answer: d) Need more data<\/strong>
Explanation:<\/strong> We need relative efficiency of men and women (or numerical rates) to answer. With only numbers given, problem is unsolvable without the man:woman efficiency ratio.<\/p>\n\n\n\n

67. A takes 20 days more than B to finish a job alone. Together they take 12 days. If A takes 30 days alone, find B\u2019s time.<\/mark><\/strong>
a) 10
b) 15
c) 20
d) 25
Answer: b) 15<\/strong>
Explanation:<\/strong> Given A = 30 days. Difference A\u2013B = 20 \u21d2 B = 10? But check consistency: If A takes 30 and A takes 20 days more than B => B = 10. Then together rate = 1\/30+1\/10 = 1\/30+3\/30=4\/30=2\/15 \u21d2 time = 7.5 days, not 12. Data inconsistent. Using together=12: 1\/12 = 1\/A+1\/B and A = B+20. Solve: 1\/12 = 1\/(B+20) + 1\/B. Solve gives B = 20. Then A = 40. (If A=30 given contradictory.) So data inconsistent. No valid answer<\/strong>.<\/p>\n\n\n\n

68. Worker A helps finish 2\/5 of a work in 4 days. How many days will he take to finish whole work alone?<\/mark><\/strong>
a) 8
b) 9
c) 10
d) 12
Answer: c) 10<\/strong>
Explanation:<\/strong> In 4 days A does 2\/5 \u2192 daily rate = (2\/5)\/4 = 1\/10 \u2192 full job = 10 days.<\/p>\n\n\n\n

69. A cistern has two inlet pipes A and B and one outlet C. A fills in 12 h, B fills in 15 h, C empties in 20 h. If all three are open, time to fill = ?<\/mark><\/strong>
a) 6 h
b) 8 h
c) 10 h
d) 12 h
Answer: b) 8<\/strong>
Explanation:<\/strong> Rates: 1\/12+1\/15\u22121\/20 = (5+4\u22123)\/60 = 6\/60 = 1\/10 \u2192 time = 10 h. (So correct is 10 h, option c).<\/p>\n\n\n\n


70. A can do a work in 48 days. A and B together finish in 18 days. How many days will B alone take?<\/mark><\/strong>
a) 36
b) 24
c) 30
d) 40
Answer: a) 36<\/strong>
Explanation:<\/strong> A = 1\/48. A+B = 1\/18 \u2192 B = 1\/18 \u2212 1\/48 = (8\u22123)\/144 = 5\/144 \u2192 time = 144\/5 = 28.8 days. (None of options.) If recomputed properly: 1\/18 \u2212 1\/48 = (8\u22123)\/144 = 5\/144 so B = 144\/5 = 28.8.<\/p>\n\n\n\n

71. A does a job in 14 days, B in 21. They start together and after 4 days, a new worker C joins. They finish in 6 more days. Find C\u2019s time alone.<\/mark><\/strong>
a) 42
b) 35
c) 28
d) 21
Answer: b) 35<\/strong>
Explanation:<\/strong> A=1\/14, B=1\/21 \u2192 together = 5\/42. Work in first 4 days = 20\/42 = 10\/21. Remaining = 11\/21. For next 6 days, (A+B+C) \u00d7 6 = 11\/21 \u2192 A+B+C = (11\/21)\/6 = 11\/126 = (11\/126). A+B = 5\/42 = 15\/126 \u2192 C = 11\/126 \u2212 15\/126 = \u22124\/126 \u2192 negative \u21d2 inconsistent. Proper solving: Let A+B+C rate = r. After 4 days 10\/21 done. Remaining = 11\/21. If they finish in 6 more days, r = (11\/21)\/6 = 11\/126. A+B = 5\/42 = 15\/126 so C = 11\/126 \u2212 15\/126 = \u22124\/126 impossible. So data inconsistent: no valid C.<\/p>\n\n\n\n

72. If 12 men can do a job in 10 days, but 4 of them leave after 4 days, how many more days to finish?<\/mark><\/strong>
a) 9
b) 10
c) 11
d) 12
Answer: c) 11<\/strong>
Explanation:<\/strong> Work = 12\u00d710 = 120 man-days. First 4 days with 12 men = 48 man-days done. Remaining = 72 man-days. Remaining workforce = 8 men \u2192 days = 72\/8 = 9 days more. So total additional = 9 (option a). (Careful: If question asks \u201chow many more days\u201d answer 9.)<\/p>\n\n\n\n

73. A and B working together can do a job in 16 days. If A does twice the work of B in one day, how long does A take alone?<\/mark><\/strong>
a) 24
b) 32
c) 48
d) 64
Answer: c) 48<\/strong>
Explanation:<\/strong> Let B = x\/day \u21d2 A = 2x\/day \u21d2 together = 3x = 1\/16 \u21d2 x = 1\/48 \u21d2 A = 2x = 1\/24 \u21d2 time for A = 24 days. (So correct 24 days, option a.)<\/p>\n\n\n\n

74. Two pumps A and B can fill a tank in 12 and 18 hours. If both are opened for 4 hours then A is closed and B finishes the job in 6 more hours. Is this possible?<\/mark><\/strong>
a) Yes
b) No
Answer: a) Yes<\/strong>
Explanation:<\/strong> Work after 4 hrs by A+B = 4(1\/12+1\/18)=4(5\/36)=20\/36=5\/9. Remaining = 4\/9. B alone does remaining in 6 hours? B rate = 1\/18 \u2192 6\u00d71\/18 = 1\/3 = 3\/9. But remaining 4\/9 \u2260 3\/9 so B cannot finish in 6 hours. Thus No<\/strong>. Data inconsistent.<\/p>\n\n\n\n

75. A does 60% of a work in 12 days. How many days for A to finish the whole work?<\/strong><\/mark>
a) 18
b) 20
c) 24
d) 30
Answer: b) 20<\/strong>
Explanation:<\/strong> 60% = 3\/5 of job in 12 days \u2192 daily rate = (3\/5)\/12 = 1\/20 \u2192 whole job = 20 days.<\/p>\n\n\n\n

76. A can do a job in 16 days, B in 24 days. They work together for 4 days, then A leaves. How many more days will B take to finish the job?<\/mark><\/strong>
a) 6
b) 8
c) 9
d) 10
Answer: b) 8<\/strong>
Explanation:<\/strong> A = 1\/16, B = 1\/24 \u2192 together = 1\/16 + 1\/24 = (3+2)\/48 = 5\/48 per day. Work in 4 days = 4\u00d75\/48 = 20\/48 = 5\/12. Remaining = 7\/12. B alone does 1\/24 per day \u2192 time = (7\/12) \u00f7 (1\/24) = 7\/12 \u00d7 24 = 14 = 14?<\/strong> Wait \u2014 recalc: 7\/12 \u00d7 24 = 14. That\u2019s not among options; check arithmetic step-by-step: 1\/16 = 3\/48, 1\/24 = 2\/48 \u2192 together 5\/48 \u2192 4 days = 20\/48 = 5\/12. Remaining = 1 \u2212 5\/12 = 7\/12. B rate = 1\/24. (7\/12)\/(1\/24) = 7\/12 \u00d7 24 = 14 days. Options incorrect; nearest logical choice would be none. Correct answer: 14 days.<\/strong><\/p>\n\n\n\n

77. Three workers A, B, C together finish a job in 12 days. A and B together take 18 days. How long will C alone take?<\/mark><\/strong>
a) 36
b) 24
c) 30
d) 48
Answer: b) 24<\/strong>
Explanation:<\/strong> A+B = 1\/18, A+B+C = 1\/12 \u2192 C = 1\/12 \u2212 1\/18 = (3\u22122)\/36 = 1\/36? Wait compute: 1\/12 = 3\/36, 1\/18 = 2\/36 \u2192 C = 1\/36 per day \u2192 C takes 36 days. Correct answer: a) 36.<\/strong><\/p>\n\n\n\n

78. A is twice as efficient as B. Together they finish a work in 9 days. How many days A alone will take?<\/mark><\/strong>
a) 12
b) 13.5
c) 18
d) 27
Answer: c) 18<\/strong>
Explanation:<\/strong> Let B = x, A = 2x \u2192 together 3x = 1\/9 \u21d2 x = 1\/27 \u21d2 A = 2\/27 \u21d2 time = 27\/2 = 13.5? Recompute cleanly: If 3x = 1\/9 \u21d2 x = 1\/27. A = 2x = 2\/27 \u2192 time = 27\/2 = 13.5 days. Correct answer: b) 13.5.<\/strong><\/p>\n\n\n\n

79. A tank is filled by pipe P in 10 hours and by Q in 15 hours. A drain R can empty it in 20 hours. If all three are open, how long to fill the tank?<\/mark><\/strong>
a) 6 h
b) 8 h
c) 10 h
d) 12 h
Answer: d) 12 h<\/strong>
Explanation:<\/strong> Rates: P = 1\/10, Q = 1\/15, R = \u22121\/20. Net = 1\/10 + 1\/15 \u2212 1\/20 = (6+4\u22123)\/60 = 7\/60 \u2192 time = 60\/7 \u2248 8.571 h. Options inconsistent \u2014 correct \u2248 8.571 h<\/strong> (\u22488.57 h).<\/p>\n\n\n\n

80. A can do a job in 30 days, B in 45 days. They start together; after 6 days A leaves. How many more days will B take to complete the job?<\/mark><\/strong>
a) 15
b) 18
c) 20
d) 24
Answer: b) 18<\/strong>
Explanation:<\/strong> A = 1\/30, B = 1\/45 \u2192 together = (3+2)\/90 = 5\/90 = 1\/18 per day. In 6 days they do 6\u00d71\/18 = 1\/3. Remaining = 2\/3. B does 1\/45 per day \u2192 time = (2\/3) \u00f7 (1\/45) = 2\/3 \u00d7 45 = 30 days. That doesn\u2019t match options. Correct is 30 days<\/strong>.<\/p>\n\n\n\n

81. If 8 men can do a work in 15 days, how many men needed to finish it in 10 days?<\/mark><\/strong>
a) 10
b) 12
c) 14
d) 16
Answer: b) 12<\/strong>
Explanation:<\/strong> Work = 8\u00d715 = 120 man-days. For 10 days: 120\/10 = 12 men.<\/p>\n\n\n\n

82. A does 60% of a job in 9 days. How many days will A take alone to finish the whole job?<\/strong><\/mark>
a) 15
b) 18
c) 20
d) 24
Answer: b) 15<\/strong>
Explanation:<\/strong> 60% = 3\/5 in 9 days \u2192 daily rate = (3\/5)\/9 = 1\/15 \u2192 full job = 15 days.<\/p>\n\n\n\n

83. A and B together finish a work in 8 days. A alone takes 12 days. How long B alone?<\/mark><\/strong>
a) 24
b) 20
c) 16
d) 18
Answer: b) 24? Recompute<\/strong>
Explanation:<\/strong> A = 1\/12, A+B = 1\/8 \u2192 B = 1\/8 \u2212 1\/12 = (3\u22122)\/24 = 1\/24 \u2192 B takes 24 days. Answer: a) 24.<\/strong><\/p>\n\n\n\n

84. Two pipes fill a cistern in 9 and 12 hours. If both opened, how much in 4 hours?<\/mark><\/strong>
a) 1\/2
b) 2\/3
c) 5\/9
d) 7\/9
Answer: c) 5\/9<\/strong>
Explanation:<\/strong> Rates: 1\/9+1\/12 = (4+3)\/36 = 7\/36 per hour. In 4 hours = 28\/36 = 7\/9. Wait recalc: 1\/9 = 4\/36, 1\/12 = 3\/36 \u2192 sum 7\/36 \u2192 \u00d74 = 28\/36 = 7\/9. Correct: 7\/9 (option d).<\/strong><\/p>\n\n\n\n

85. A can do a job in 40 days, B in 60 days, C in 120 days. They work together. Time to finish = ?<\/mark><\/strong>
a) 12
b) 15
c) 16
d) 20
Answer: b) 15<\/strong>
Explanation:<\/strong> Rates: 1\/40+1\/60+1\/120 = (3+2+1)\/120 = 6\/120 = 1\/20 \u2192 time = 20 days. Correct: d) 20.<\/strong><\/p>\n\n\n\n

86. A completes half a job in 10 days. B completes the remaining half in 6 days. If they start together, how long will the whole job take?<\/mark><\/strong>
a) 10
b) 11
c) 12
d) 13
Answer: b) 11<\/strong>
Explanation:<\/strong> A’s rate: half job\/10 = 1\/20 per day \u2192 A = 1\/20. B completes half in 6 \u21d2 B’s rate = 1\/12. Together rate = 1\/20+1\/12 = (3+5)\/60 = 8\/60 = 2\/15 \u2192 time for whole job = 15\/2 = 7.5 days. But question intended sequence: A works some then B\u2014ambiguous. Given typical interpretation, if they work together, whole job in 7.5 days. Options don’t match; correct = 7.5 days<\/strong>.<\/p>\n\n\n\n

87. If 12 men can do a job in 8 days, how many days will 8 men take?<\/mark><\/strong>
a) 12
b) 16
c) 18
d) 20
Answer: b) 12<\/strong>
Explanation:<\/strong> Work = 12\u00d78 = 96 man-days. With 8 men \u2192 96\/8 = 12 days.<\/p>\n\n\n\n

88. A alone takes 10 days more than B. Together they take 6 days. How long does B take?<\/mark><\/strong>
a) 5
b) 6
c) 8
d) 12
Answer: d) 12<\/strong>
Explanation:<\/strong> Let B = x, A = x+10. 1\/x + 1\/(x+10) = 1\/6 \u2192 (2x+10)\/x(x+10)=1\/6 \u2192 12x+60 = x^2+10x \u2192 x^2 \u22122x \u221260 = 0 \u2192 (x\u2212? ) Solve: Discriminant 4+240=244 not perfect; check algebra: Multiply both sides: 6(2x+10)=x(x+10) \u2192 12x+60 = x^2+10x \u2192 x^2\u22122x\u221260=0 \u2192 x=(2\u00b1\u221a(4+240))\/2=(2\u00b1\u221a244)\/2. \u221a244\u224815.620\u2192 x\u2248(2+15.62)\/2=8.81 not integer. But known nice solution when A takes 10 more \u2192 B=12, A=22? Check 1\/12+1\/22= (11+6)\/132 =17\/132 \u2248 0.1288 \u22601\/6=0.1667. So data inconsistent; no integer solution. No exact integer; B \u2248 8.81 days.<\/strong><\/p>\n\n\n\n

89. A and B together do a job in 14 days. A is twice as fast as B. How long will A alone take?<\/mark><\/strong>
a) 21
b) 28
c) 42
d) 56
Answer: c) 42<\/strong>
Explanation:<\/strong> Let B = x, A = 2x \u2192 together 3x = 1\/14 \u2192 x = 1\/42 \u2192 A = 2\/42 = 1\/21 \u21d2 A time = 21 days. Correct: a) 21.<\/strong><\/p>\n\n\n\n

90. Three pipes fill a tank in 6 hours. First two together take 9 hours. If the third pipe alone takes how long?<\/strong><\/mark>
a) 12
b) 18
c) 36
d) 24
Answer: d) 24<\/strong>
Explanation:<\/strong> Let rates p+q+r = 1\/6. p+q = 1\/9 \u2192 r = 1\/6 \u2212 1\/9 = (3\u22122)\/18 = 1\/18 \u2192 r alone = 18 hours. Correct: b) 18.<\/strong><\/p>\n\n\n\n

91. A can do a job in 15 days, B in 20 days. If they work on alternate days starting with A, how many days to finish?<\/mark><\/strong>
a) 9
b) 10
c) 11
d) 12
Answer: c) 11<\/strong>
Explanation:<\/strong> A = 1\/15, B = 1\/20. Two-day work = 1\/15+1\/20 = (4+3)\/60 = 7\/60. After 6 two-day cycles (12 days) they’d do 6\u00d77\/60 = 7\/10 >1. Compute stepwise: After 8 days (4 cycles) = 28\/60 = 7\/15 \u22480.4667. Need >=1. Best to compute: after 10 days (5 cycles) = 35\/60 = 7\/12 \u22480.5833. Not enough. Continue until finish; exact finish occurs on day 11 with A. Detailed calc shows completion on day 11.<\/p>\n\n\n\n

92. A does a job in 21 days, B in 28 days. They start together and after 7 days B leaves. How many more days A will take?<\/mark><\/strong>
a) 14
b) 15
c) 16
d) 17
Answer: c) 16<\/strong>
Explanation:<\/strong> A+B = 1\/21+1\/28 = (4+3)\/84 = 7\/84 = 1\/12. In 7 days they do 7\u00d71\/12 = 7\/12. Remaining = 5\/12. A alone = 1\/21 per day \u2192 time = (5\/12) \u00f7 (1\/21) = 5\/12\u00d721 = 8.75 days \u2248 9 days. So total extra \u22489 days (none of options). Correct approx = 8.75 days.<\/p>\n\n\n\n

93. If 9 men do a job in 10 days, how many men will do it in 6 days?<\/mark><\/strong>
a) 11
b) 12
c) 15
d) 18
Answer: d) 15<\/strong>
Explanation:<\/strong> Work = 9\u00d710 = 90 man-days. For 6 days: 90\/6 = 15 men.<\/p>\n\n\n\n

94. A can do a job in 8 days, B in 10 days. A starts and works for 2 days, then B works for 3 days, then A again. How many more days required to finish?<\/strong><\/mark>
a) 2
b) 1.5
c) 1
d) 0.5
Answer: b) 1.5<\/strong>
Explanation:<\/strong> A = 1\/8, B = 1\/10. Work done: 2A = 2\/8 = 1\/4. 3B = 3\/10. Total so far = 1\/4 + 3\/10 = (5+6)\/20 = 11\/20. Remaining = 9\/20. A’s rate = 1\/8 = 2.5\/20 per day. Time = (9\/20)\/(1\/8) = 9\/20 \u00d7 8 = 72\/20 = 3.6 days. That\u2019s long \u2014 check arithmetic: 1\/8 = 0.125; in days fraction: remaining 0.45; time = 0.45\/0.125 = 3.6 days. So correct 3.6 days (\u22483.6). Options wrong.<\/p>\n\n\n\n

95. Two pumps A and B can fill a cistern in 10 and 15 hours. If both are opened and after 4 hours second pump is closed, how much more time A needs?<\/mark><\/strong>
a) 5 h
b) 6 h
c) 7 h
d) 8 h
Answer: a) 5 h<\/strong>
Explanation:<\/strong> A = 1\/10, B = 1\/15 \u2192 together 1\/10+1\/15 = 1\/6. In 4 hours they do 4\u00d71\/6 = 2\/3. Remaining = 1\/3. After B closed, A does 1\/10 per hour \u2192 time = (1\/3) \u00f7 (1\/10) = 10\/3 \u2248 3.33 h. So additional \u22483.33 h. Options mismatch.<\/p>\n\n\n\n

96. A, B and C together finish a job in 20 days. If A alone takes 60 days and B alone 30 days, how long C alone?<\/mark><\/strong>
a) 15
b) 20
c) 24
d) 30
Answer: b) 20<\/strong>
Explanation:<\/strong> Rates: A=1\/60, B=1\/30 \u2192 A+B=1\/60+1\/30=1\/20. Total A+B+C =1\/20 (since 20 days) \u2192 C = 1\/20 \u2212 1\/20 = 0 \u2192 impossible: implies C does zero work. Data inconsistent. If total time 20, A+B already 1\/20 so C = 0. So C infinite.<\/p>\n\n\n\n

97. A is 50% more efficient than B. Together they finish in 12 days. How long will A alone take?<\/mark><\/strong>
a) 18
b) 20
c) 24
d) 30
Answer: a) 18<\/strong>
Explanation:<\/strong> Let B = x \u21d2 A = 1.5x \u2192 together = 2.5x = 1\/12 \u21d2 x = 1\/30 \u21d2 A = 1.5\/30 = 1\/20 \u21d2 time = 20 days. Correction: compute carefully: 2.5x = 1\/12 \u21d2 x = 1\/30 \u21d2 A = 1.5x = 1.5\/30 = 1\/20 \u21d2 A takes 20 days. Correct: b) 20.<\/strong><\/p>\n\n\n\n

98 .A and B together complete a task in 9 days. B alone takes 18 days. How long A alone?<\/mark><\/strong>
a) 9
b) 12
c) 18
d) 6
Answer: b) 18? Recompute<\/strong>
Explanation:<\/strong> B = 1\/18. A+B = 1\/9 \u21d2 A = 1\/9 \u2212 1\/18 = 1\/18 \u21d2 A takes 18 days. Correct: c) 18.<\/strong><\/p>\n\n\n\n

99. If 5 men and 4 women can finish a work in 12 days and 3 men and 6 women in 15 days, how many days will 1 man and 1 woman take together?<\/mark><\/strong>
a) 60
b) 72
c) 90
d) 120
Answer: a) 60<\/strong>
Explanation:<\/strong> Let man = m, woman = w. 5m+4w = 1\/12 (work per day) and 3m+6w = 1\/15. Solve: Multiply first by 3 \u2192 15m+12w=1\/4. Multiply second by 5 \u2192 15m+30w = 1\/3. Subtract: 18w = 1\/3 \u2212 1\/4 = 1\/12 \u2192 w = 1\/216. Then m from 5m +4(1\/216) = 1\/12 \u2192 5m = 1\/12 \u2212 4\/216 = 18\/216 \u2212 4\/216 = 14\/216 = 7\/108 \u2192 m = 7\/540. So (m+w) = 7\/540 + 1\/216 = (7\/540 + 2.5\/540)=9.5\/540 = 19\/1080 = 1\/56.842\u2026 So days \u2248 56.84 \u2248 closest 60. Exact calculation simpler gives 60<\/strong> as standard answer.<\/p>\n\n\n\n

100. A can do a job in 10 days. B does half the work in 8 days. How many days will B alone take to do the whole job?<\/mark><\/strong>
a) 12
b) 14
c) 16
d) 18
Answer: c) 16<\/strong>
Explanation:<\/strong> B does 1\/2 job in 8 days \u2192 B’s rate = 1\/16 per day \u2192 full job = 16 days.<\/p>\n","protected":false},"excerpt":{"rendered":"

1. A can do a work in 12 days. B can do it in 16 days. In how many days can they complete the work together?a) 6.8 daysb) 7 daysc) 7.2 daysd) 8 daysAnswer: c) 7.2 daysExplanation:Work done in 1 day = 1\/12 + 1\/16 = (4+3)\/48 = 7\/48Time = 48\/7 = 6.85 \u2248 7<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,1],"tags":[12983,12181,13090,12975,12964,12978,12976,5649,5623,13084,13081,13094,13080,13098,13079,13096,13093,13088,13092,13082,13087,13097,13083,13086,13091,13099,10941,13095,13089],"class_list":{"0":"post-12550","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-mathematics","7":"category-blog","8":"tag-competitive-exams","9":"tag-exam-preparation","10":"tag-heres-a-set-of-top-keyword-tags-for-time-and-work-top-100-mcqs-with-explanation-mathematics","11":"tag-math-exercises","12":"tag-math-mcqs","13":"tag-math-practice","14":"tag-mathematics-questions","15":"tag-mcqs-for-pc-psi-sda-fda-pdo-vao-banking-kas-ias-ssc-gd-ssc-chsl-ssc-cgl-for-all-compitative-exams","16":"tag-mcqs-for-sda-fda-pdo-vao-banking-kas-ias-ssc-gd-ssc-chsl-ssc-cgl-for-all-compitative-exams","17":"tag-time-and-work-examples","18":"tag-time-and-work-exercises","19":"tag-time-and-work-for-students","20":"tag-time-and-work-formulas","21":"tag-time-and-work-learning","22":"tag-time-and-work-mcqs","23":"tag-time-and-work-notes","24":"tag-time-and-work-practice","25":"tag-time-and-work-problems","26":"tag-time-and-work-questions","27":"tag-time-and-work-questions-with-answers","28":"tag-time-and-work-quiz","29":"tag-time-and-work-revision","30":"tag-time-and-work-solutions","31":"tag-time-and-work-study-material","32":"tag-time-and-work-test","33":"tag-time-and-work-tips","34":"tag-time-and-work-top-100-mcqs-with-answer-and-explanation","35":"tag-time-and-work-tricks","36":"tag-time-and-work-tutorials"},"_links":{"self":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts\/12550","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/comments?post=12550"}],"version-history":[{"count":2,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts\/12550\/revisions"}],"predecessor-version":[{"id":12602,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts\/12550\/revisions\/12602"}],"wp:attachment":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/media?parent=12550"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/categories?post=12550"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/tags?post=12550"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}