Chain rule is nothing but proportion, and the whole chapter rests on one question you must ask before you write anything. If this quantity goes up, does the other one go up or come down? More workers finish the job in fewer days, so that is inverse. More workers produce more goods, so that is direct. Ask it once for every pair in the question and the equation writes itself.
The mistake students make is rushing to cross multiply without deciding the direction, and then the answer comes out upside down, and the paper will have that upside down value waiting in the options. So slow down for five seconds at the start. Also watch the units, because if days are given in one place and hours in another, convert first.
Learn the single formula below properly and you can leave the rest, because everything in this chapter comes out of it.
Chain Rule Formulas
The one formula that covers the chapter
(M1 × D1 × H1) ÷ W1 = (M2 × D2 × H2) ÷ W2
Where M = number of men, D = number of days, H = hours worked per day, W = amount of work done.
Drop whatever the question does not mention.
Direct proportion
One goes up, the other goes up. a1 ÷ b1 = a2 ÷ b2
Men and work, days and work, speed and distance.
Inverse proportion
One goes up, the other comes down. a1 × b1 = a2 × b2
Men and days, speed and time, pipes and time to fill.
Deciding the direction
Take each column against the answer column. Direct keeps the ratio as it is, inverse flips it. Decide this before you cross multiply.
Unitary method, the fallback
Bring it down to one unit, then scale up. Slower by a line, but never goes wrong.
60 Chain Rule Aptitude Questions and Answers (Solved MCQs)
Question 1. If 8 workers can complete a job in 15 days, how many days will 12 workers take to complete the same job, assuming equal efficiency?
a) 8 days
b) 10 days
c) 12 days
d) 14 days
Answer:
b) 10 days — Workers and days are inversely proportional. Required days = (8×15)/12 = 10 days.
Question 2. If 6 machines produce 1,800 units in 5 hours, how many units will 10 machines produce in 8 hours at the same rate?
a) 4,200
b) 4,500
c) 4,800
d) 5,000
Answer:
c) 4,800 — Production is directly proportional to both machines and time. Required production = 1800×(10/6)×(8/5) = 4,800 units.
Question 3. If 15 men can build a wall in 24 days, how many men are required to build the same wall in 18 days?
a) 18
b) 20
c) 22
d) 24
Answer:
b) 20 — Men and days are inversely proportional. Required men = (15×24)/18 = 20.
Question 4. If 12 cows consume 720 kg of fodder in 15 days, how much fodder will 18 cows consume in 20 days?
a) 1,200 kg
b) 1,320 kg
c) 1,440 kg
d) 1,560 kg
Answer:
c) 1,440 kg — Fodder consumption is directly proportional to the number of cows and days. Required fodder = 720×(18/12)×(20/15) = 1,440 kg.
Question 5. If 9 typists type 540 pages in 6 hours, how many pages can 15 typists type in 8 hours?
a) 1,000
b) 1,100
c) 1,200
d) 1,350
Answer:
c) 1,200 — Pages typed are directly proportional to typists and time. Required pages = 540×(15/9)×(8/6) = 1,200.
Question 6. If 16 workers working 7 hours a day complete a task in 15 days, how many days will 20 workers working 6 hours a day take?
a) 12 days
b) 13 days
c) 14 days
d) 15 days
Answer:
c) 14 days — Total work is proportional to workers×hours×days. Required days = (16×7×15)/(20×6) = 14 days.
Question 7. If 5 pumps can fill a tank in 12 hours, how many pumps are needed to fill it in 7.5 hours?
a) 6
b) 7
c) 8
d) 9
Answer:
c) 8 — Pumps and time are inversely proportional. Required pumps = (5×12)/7.5 = 8.
Question 8. If 18 labourers can dig a trench 120 metres long in 10 days, what length can 24 labourers dig in 15 days?
a) 200 m
b) 220 m
c) 240 m
d) 260 m
Answer:
c) 240 m — Length dug is directly proportional to labourers and days. Required length = 120×(24/18)×(15/10) = 240 m.
Question 9. If 7 printers print 8,400 sheets in 4 hours, how many printers are required to print 18,000 sheets in 6 hours?
a) 8
b) 9
c) 10
d) 12
Answer:
c) 10 — Printers are directly proportional to sheets and inversely proportional to time. Required printers = 7×(18000/8400)×(4/6) = 10.
Question 10. If 25 men can complete a road in 32 days, after working for 8 days, 5 men leave. In how many additional days will the remaining work be completed?
a) 25 days
b) 28 days
c) 30 days
d) 32 days
Answer:
c) 30 days — Total work = 25×32 = 800 man-days. Work completed = 25×8 = 200 man-days. Remaining work = 600 man-days. With 20 men, required time = 600/20 = 30 days.
Question 11. If 20 workers manufacture 600 articles in 12 days, how many workers are required to manufacture 900 articles in 10 days?
a) 30
b) 32
c) 36
d) 40
Answer:
c) 36 — Workers are directly proportional to output and inversely proportional to days. Required workers = 20×(900/600)×(12/10) = 36.
Question 12. If 14 horses consume 294 kg of grain in 7 days, how many days will 630 kg of grain last for 18 horses?
a) 10 days
b) 11 days
c) 12 days
d) 14 days
Answer:
c) 12 days — Grain per horse per day = 294/(14×7) = 3 kg. Daily requirement for 18 horses = 54 kg. Number of days = 630/54 = 11⅔ days. Therefore, the grain lasts for 11⅔ days, so none of the whole-number options is exact.
Question 13. If 8 men or 12 women can complete a job in 20 days, what is the ratio of the efficiency of a man to that of a woman?
a) 2:3
b) 3:2
c) 4:3
d) 5:4
Answer:
b) 3:2 — Since 8 men and 12 women complete the same work in the same time, 8 men’s efficiency = 12 women’s efficiency. Therefore, one man’s efficiency : one woman’s efficiency = 12:8 = 3:2.
Question 14. If 10 workers working 8 hours a day make 400 chairs in 5 days, how many chairs will 16 workers working 6 hours a day make in 10 days?
a) 840
b) 900
c) 960
d) 1,000
Answer:
c) 960 — Production is directly proportional to workers, hours and days. Required chairs = 400×(16/10)×(6/8)×(10/5) = 960.
Question 15. If 12 men working 9 hours a day finish a task in 16 days, how many men working 8 hours a day are required to finish twice the work in 18 days?
a) 20
b) 22
c) 24
d) 27
Answer:
c) 24 — Required men = 12×(9/8)×(16/18)×2 = 24.
Question 16. If 24 workers working 8 hours a day complete a job in 15 days, how many workers working 10 hours a day are required to complete the same job in 12 days?
a) 20
b) 22
c) 24
d) 26
Answer:
c) 24 — Total work = workers × hours × days. Required workers = (24×8×15)/(10×12) = 24.
Question 17. If 18 machines manufacture 5,400 components in 12 hours, how many components will 25 machines manufacture in 18 hours?
a) 10,500
b) 11,000
c) 11,250
d) 12,000
Answer:
c) 11,250 — Output is directly proportional to machines and hours. Required output = 5400×(25/18)×(18/12) = 11,250 components.
Question 18. Thirty men working 6 hours daily can complete a project in 24 days. After 8 days, 10 more men join and everyone works 8 hours daily. In how many additional days will the remaining work be completed?
a) 8 days
b) 9 days
c) 10 days
d) 12 days
Answer:
b) 9 days — Total work = 30×6×24 = 4320 man-hours. Work completed = 30×6×8 = 1440 man-hours. Remaining work = 2880 man-hours. New daily work = 40×8 = 320 man-hours. Required days = 2880/320 = 9.
Question 19. If 16 men or 24 women can complete a task in 30 days, how many days will 12 men and 12 women take to complete the task?
a) 20 days
b) 22 days
c) 24 days
d) 25 days
Answer:
a) 20 days — Since 16 men = 24 women, 1 woman = 2/3 man. Thus, 12 men and 12 women are equivalent to 12+8 = 20 men. Total work = 16×30 = 480 man-days. Required time = 480/20 = 24 days. Therefore, the correct answer is c) 24 days.
Question 20. If 12 pumps can empty a reservoir in 18 hours, after 6 hours 4 pumps stop working. How many more hours will the remaining pumps take to empty the reservoir?
a) 15 hours
b) 16 hours
c) 18 hours
d) 20 hours
Answer:
c) 18 hours — Total work = 12×18 = 216 pump-hours. Work completed in 6 hours = 12×6 = 72 pump-hours. Remaining work = 144 pump-hours. With 8 pumps, required time = 144/8 = 18 hours.
Question 21. If 40 workers can construct 600 metres of road in 15 days, how many workers are required to construct 900 metres of the same road in 18 days?
a) 45
b) 48
c) 50
d) 54
Answer:
c) 50 — Workers are directly proportional to road length and inversely proportional to days. Required workers = 40×(900/600)×(15/18) = 50.
Question 22. If 25 cows consume 3,000 kg of fodder in 24 days, for how many days will 4,500 kg of fodder last for 30 cows?
a) 28 days
b) 30 days
c) 32 days
d) 36 days
Answer:
b) 30 days — Days are directly proportional to fodder and inversely proportional to cows. Required days = 24×(4500/3000)×(25/30) = 30 days.
Question 23. Eight identical machines working 9 hours daily produce 5,760 items in 10 days. How many machines working 8 hours daily are required to produce 10,240 items in 12 days?
a) 10
b) 12
c) 14
d) 16
Answer:
b) 12 — Required machines = 8×(10240/5760)×(9/8)×(10/12) = 12.
Question 24. If 20 workers working 7 hours daily earn ₹84,000 in 12 days, how much will 15 workers working 8 hours daily earn in 18 days at the same wage rate?
a) ₹96,000
b) ₹1,02,000
c) ₹1,08,000
d) ₹1,12,000
Answer:
c) ₹1,08,000 — Wages are directly proportional to workers, hours and days. Required wages = 84000×(15/20)×(8/7)×(18/12) = ₹1,08,000.
Question 25. If 14 workers can pack 2,520 boxes in 9 days, how many days will 21 workers take to pack 5,880 boxes?
a) 12 days
b) 13 days
c) 14 days
d) 15 days
Answer:
c) 14 days — Days are directly proportional to the number of boxes and inversely proportional to workers. Required days = 9×(5880/2520)×(14/21) = 14 days.
Question 26. A camp has food for 240 people for 36 days. After 12 days, 60 people leave the camp. For how many more days will the remaining food last?
a) 28 days
b) 30 days
c) 32 days
d) 36 days
Answer:
c) 32 days — Total food = 240×36 person-days. Food consumed in 12 days = 240×12. Remaining food = 240×24 person-days. After 60 people leave, 180 people remain. Remaining days = (240×24)/180 = 32.
Question 27. If 10 men and 15 women complete a job in 12 days, while 10 men alone complete it in 30 days, in how many days will 15 women alone complete the job?
a) 18 days
b) 20 days
c) 22 days
d) 24 days
Answer:
b) 20 days — Work done per day by 10 men and 15 women = 1/12. Work done per day by 10 men = 1/30. Therefore, 15 women complete 1/12−1/30 = 1/20 of the work daily, so they take 20 days.
Question 28. If 6 tractors can plough 360 hectares in 15 days, how many tractors are required to plough 840 hectares in 21 days?
a) 8
b) 9
c) 10
d) 12
Answer:
c) 10 — Tractors are directly proportional to area and inversely proportional to days. Required tractors = 6×(840/360)×(15/21) = 10.
Question 29. Twenty-four workers were expected to complete a job in 30 days. After 10 days, only one-fourth of the work had been completed. How many additional workers of the same efficiency must be employed to finish the job on time?
a) 8
b) 10
c) 12
d) 16
Answer:
c) 12 — In 10 days, 24 workers complete 1/4 of the work. Therefore, the remaining 3/4 must be completed in 20 days. Required workers = 24×(3/4)/(1/4)×(10/20) = 36. Additional workers = 36−24 = 12.
Question 30. If 30 men working 8 hours a day can complete three-fifths of a project in 20 days, how many men working 10 hours a day are required to complete the remaining work in 8 days?
a) 32
b) 36
c) 40
d) 48
Answer:
c) 40 — Thirty men working 8 hours for 20 days complete 3/5 of the work. For the remaining 2/5, required men = 30×(8/10)×(20/8)×(2/3) = 40.
Question 31. If 18 workers working 8 hours a day can complete a job in 25 days, how many workers working 10 hours a day are required to complete 60% more work in 24 days?
a) 20
b) 22
c) 24
d) 26
Answer:
c) 24 — Required workers = 18×(8/10)×(25/24)×(160/100) = 24.
Question 32. A contractor employs 36 workers to complete a project in 40 days. After 10 days, only one-fifth of the project is completed. How many additional workers of the same efficiency are needed to finish the project on schedule?
a) 8
b) 10
c) 12
d) 14
Answer:
c) 12 — In 10 days, 36 workers complete 1/5 of the work. To complete the remaining 4/5 in 30 days, required workers = 36×(4/5)/(1/5)×(10/30) = 48. Additional workers = 48−36 = 12.
Question 33. If 24 machines working 9 hours daily produce 12,960 components in 15 days, how many machines working 8 hours daily will produce 19,200 components in 20 days?
a) 26
b) 28
c) 30
d) 32
Answer:
c) 30 — Required machines = 24×(19200/12960)×(9/8)×(15/20) = 30.
Question 34. A garrison has food for 800 soldiers for 45 days. After 15 days, 200 additional soldiers join. For how many more days will the remaining food last?
a) 20 days
b) 22 days
c) 24 days
d) 25 days
Answer:
c) 24 days — Remaining food = 800×30 soldier-days. After 200 soldiers join, total soldiers = 1,000. Remaining days = 800×30/1000 = 24.
Question 35. If 20 men or 30 women can complete a task in 36 days, in how many days will 8 men and 18 women complete the same task?
a) 30 days
b) 32 days
c) 36 days
d) 40 days
Answer:
c) 36 days — Since 20 men = 30 women, 1 woman = 2/3 man. Thus, 18 women are equivalent to 12 men. Total workforce = 8+12 = 20 men, who complete the work in 36 days.
Question 36. Fifteen pumps working 6 hours daily can fill 9 identical tanks in 12 days. How many pumps working 8 hours daily are required to fill 20 such tanks in 15 days?
a) 20
b) 22
c) 24
d) 25
Answer:
a) 20 — Required pumps = 15×(20/9)×(6/8)×(12/15) = 20.
Question 37. If 16 workers working 7 hours daily manufacture 4,480 articles in 20 days, how many articles will 25 workers working 8 hours daily manufacture in 28 days?
a) 10,000
b) 10,500
c) 11,000
d) 11,200
Answer:
c) 11,200 — Required production = 4480×(25/16)×(8/7)×(28/20) = 11,200 articles.
Question 38. A contractor planned to complete a road in 48 days using 50 workers. After 16 days, only one-fourth of the road was completed. How many workers must be employed in total to finish the road within the remaining time?
a) 70
b) 72
c) 75
d) 80
Answer:
c) 75 — Fifty workers complete 1/4 of the road in 16 days. The remaining 3/4 must be completed in 32 days. Required workers = 50×(3/4)/(1/4)×(16/32) = 75.
Question 39. If 32 workers working 9 hours daily earn ₹3,45,600 in 15 days, how much will 24 workers working 8 hours daily earn in 20 days at the same wage rate?
a) ₹2,96,000
b) ₹3,00,000
c) ₹3,07,200
d) ₹3,12,000
Answer:
c) ₹3,07,200 — Required wages = 345600×(24/32)×(8/9)×(20/15) = ₹3,07,200.
Question 40. Twelve men and 18 women complete a job in 20 days. If 8 men alone can complete the same job in 60 days, in how many days can 18 women alone complete it?
a) 30 days
b) 36 days
c) 40 days
d) 45 days
Answer:
a) 30 days — Eight men complete 1/60 of the work daily, so 12 men complete 12/(8×60) = 1/40 daily. The combined group completes 1/20 daily. Therefore, 18 women complete 1/20−1/40 = 1/40 daily and would take 40 days. Hence, the correct answer is c) 40 days.
Question 41. If 8 excavators can dig a trench 1,200 metres long, 3 metres wide and 2 metres deep in 15 days, how many excavators are needed to dig a trench 1,800 metres long, 4 metres wide and 2.5 metres deep in 20 days?
a) 12
b) 14
c) 15
d) 16
Answer:
c) 15 — Work is proportional to length×width×depth. Required excavators = 8×(1800/1200)×(4/3)×(2.5/2)×(15/20) = 15.
Question 42. Twenty-four workers working 6 hours daily complete half of a project in 18 days. How many workers working 9 hours daily are required to complete the remaining half in 8 days?
a) 30
b) 32
c) 36
d) 40
Answer:
c) 36 — Since both parts represent half the project, 24×6×18 = M×9×8. Therefore, M = 36.
Question 43. If 30 cows consume 4,500 kg of fodder in 20 days, how many kilograms of fodder are required for 45 cows for 32 days if each cow’s daily consumption increases by 20%?
a) 11,520 kg
b) 12,000 kg
c) 12,480 kg
d) 12,960 kg
Answer:
d) 12,960 kg — Required fodder = 4500×(45/30)×(32/20)×(120/100) = 12,960 kg.
Question 44. A printing press with 12 machines working 10 hours daily prints 7,20,000 pages in 15 days. After a 20% improvement in efficiency, how many days will 18 machines working 8 hours daily take to print 13,82,400 pages?
a) 18 days
b) 20 days
c) 22 days
d) 24 days
Answer:
b) 20 days — Required days = 15×(1382400/720000)×(12/18)×(10/8)×(100/120) = 20 days.
Question 45. Forty workers can complete a project in 54 days. After 18 days, 10 workers leave. Twelve days later, 15 new workers join. How many more days will the project take to finish?
a) 20 days
b) 22 days
c) 24 days
d) 26 days
Answer:
c) 24 days — Total work = 40×54 = 2,160 worker-days. Work done in the first 18 days = 40×18 = 720. Work done in the next 12 days by 30 workers = 360. Remaining work = 2160−1080 = 1080 worker-days. After 15 workers join, total workers = 45. Required time = 1080/45 = 24 days.
Question 46. Twenty-four workers working 8 hours daily can complete 75% of a project in 20 days. How many workers working 10 hours daily are required to complete the remaining project in 6 days?
a) 14
b) 16
c) 18
d) 20
Answer:
b) 16 — The first 75% requires 24×8×20 worker-hours. For the remaining 25%, required worker-hours are one-third of this amount. Thus, required workers = (24×8×20×1/3)/(10×6) = 16.
Question 47. A contractor planned to complete a project using 48 workers in 50 days. After 20 days, only 30% of the project was completed. How many additional workers of the same efficiency are required to finish the project on time?
a) 20
b) 24
c) 28
d) 32
Answer:
d) 32 — Forty-eight workers complete 30% of the work in 20 days. To complete the remaining 70% in 30 days, required workers = 48×(70/30)×(20/30) = 224/3, or 74⅔ workers. Therefore, at least 75 workers are needed, meaning 27 additional workers. Since workers must be whole numbers, none of the given options is exact.
Question 48. If 18 machines working 12 hours daily manufacture 17,280 units in 16 days, how many machines working 9 hours daily are required to manufacture 32,400 units in 20 days, if the new machines are 20% more efficient?
a) 20
b) 22
c) 24
d) 25
Answer:
d) 25 — Required machines = 18×(32400/17280)×(12/9)×(16/20)×(100/120) = 25.
Question 49. A camp has provisions for 600 people for 40 days. After 10 days, 150 more people join. After another 10 days, 250 people leave. For how many additional days will the remaining provisions last?
a) 20 days
b) 22 days
c) 24 days
d) 25 days
Answer:
c) 24 days — Total provisions = 600×40 = 24,000 person-days. Consumption in the first 10 days = 6,000. Consumption in the next 10 days by 750 people = 7,500. Remaining provisions = 10,500 person-days. After 250 people leave, 500 remain. The provisions last 10,500/500 = 21 days. Therefore, none of the options is exact.
Question 50. Thirty men working 9 hours daily can complete a project in 48 days. After 16 days, the working hours are reduced to 8 per day and 6 men leave. How many additional men must be employed to complete the project on time?
a) 12
b) 14
c) 16
d) 18
Answer:
d) 18 — Total work = 30×9×48. Work completed = 30×9×16. Remaining work must be completed in 32 days at 8 hours daily. Required total workers = (30×9×32)/(8×32) = 33.75, so at least 34 workers are required. Since 24 workers remain, 10 additional workers are needed. None of the options is exact.
Question 51. If 12 men or 18 women can complete a task in 30 days, how many days will 8 men and 12 women take to complete twice the task?
a) 30 days
b) 36 days
c) 40 days
d) 45 days
Answer:
c) 40 days — Since 12 men = 18 women, 12 women are equivalent to 8 men. Thus, the group is equivalent to 16 men. One task requires 12×30 = 360 man-days, so twice the task requires 720 man-days. Required time = 720/16 = 45 days. Therefore, the correct answer is d) 45 days.
Question 52. Eight pumps working 6 hours daily can empty three-fourths of a reservoir in 15 days. How many pumps working 10 hours daily are required to empty the remaining reservoir in 3 days?
a) 6
b) 8
c) 10
d) 12
Answer:
b) 8 — The remaining one-fourth is one-third of the completed three-fourths. Required pumps = 8×6×15×(1/3)/(10×3) = 8.
Question 53. Twenty-four workers can manufacture 4,800 articles in 16 days while working 10 hours daily. After an efficiency improvement of 25%, how many articles will 30 workers manufacture in 20 days while working 8 hours daily?
a) 7,200
b) 7,500
c) 7,800
d) 8,000
Answer:
b) 7,500 — Required articles = 4800×(30/24)×(20/16)×(8/10)×(125/100) = 7,500.
Question 54. A road 1,200 metres long, 8 metres wide and 15 centimetres thick is constructed by 40 workers in 30 days. How many workers are required to construct a road 1,800 metres long, 10 metres wide and 20 centimetres thick in 45 days?
a) 40
b) 44
c) 48
d) 50
Answer:
b) 44 — Work is proportional to length×width×thickness. Required workers = 40×(1800/1200)×(10/8)×(20/15)×(30/45) = 200/3, or 66⅔ workers. Therefore, at least 67 workers are required, so none of the options is exact.
Question 55. A factory employs 50 workers working 8 hours daily to produce 20,000 units in 25 days. Due to a 10% fall in efficiency, how many workers working 10 hours daily are required to produce 27,000 units in 30 days?
a) 45
b) 48
c) 50
d) 54
Answer:
c) 50 — Required workers = 50×(27000/20000)×(8/10)×(25/30)×(100/90) = 50.
Question 56. A garrison has provisions for 1,200 soldiers for 50 days. After 20 days, 300 soldiers leave, but the daily ration per soldier is increased by 25%. For how many more days will the remaining provisions last?
a) 28 days
b) 30 days
c) 32 days
d) 36 days
Answer:
c) 32 days — Remaining provisions = 1200×30 standard ration-days. After 300 soldiers leave, 900 remain, each consuming 1.25 times the original ration. Effective daily consumption = 900×1.25 = 1125 standard units. Remaining days = 36000/1125 = 32.
Question 57. Thirty-two workers working 7 hours daily can complete five-eighths of a project in 25 days. How many workers working 10 hours daily are required to complete the remaining work in 12 days?
a) 24
b) 26
c) 28
d) 30
Answer:
c) 28 — The remaining work is 3/8, which is 3/5 of the completed 5/8. Required workers = 32×7×25×(3/5)/(10×12) = 28.
Question 58. Fifteen men and 20 women complete a job in 18 days. Ten men and 30 women complete the same job in 20 days. In how many days will 20 men and 10 women complete it?
a) 15 5/11 days
b) 16 4/11 days
c) 17 3/11 days
d) 18 2/11 days
Answer:
b) 16 4/11 days — Let the daily efficiencies of one man and one woman be m and w. Then 15m+20w=1/18 and 10m+30w=1/20. Solving gives m=1/375 and w=7/9000. Therefore, the daily work of 20 men and 10 women is 20/375+70/9000=11/180. Required time = 180/11 = 16 4/11 days.
Question 59. A contractor employs 60 workers to complete a project in 36 days. After 12 days, 20% of the completed work is found defective and must be redone. How many additional workers are required to complete the entire project within the original deadline?
a) 4
b) 5
c) 6
d) 8
Answer:
c) 6 — Total work = 60×36 = 2,160 worker-days. Work done in 12 days = 720 worker-days, but 20% of it, or 144 worker-days, is defective. Effective completed work = 576 worker-days. Remaining work = 2,160−576 = 1,584 worker-days. Time left = 24 days. Required workers = 1,584/24 = 66. Therefore, 6 additional workers are required, so the correct answer is c) 6.
Question 60. Forty-five workers working 8 hours daily were expected to complete a project in 40 days. After 16 days, one-third of the total project remained completed instead of the planned two-fifths. How many workers working 10 hours daily are required to complete the remaining project in the next 20 days?
a) 42
b) 45
c) 48
d) 50
Answer:
c) 48 — The original rate implies total work = 45×8×40 = 14,400 worker-hours. One-third has been completed, so two-thirds remains, equal to 9,600 worker-hours. Required workers = 9600/(10×20) = 48.
