Time & Work MCQs With Answers
Men building walls and pipes filling tanks are classic aptitude puzzles with a simple core idea: work done per day. These time and work MCQs cover men and days, men and women working together, two or three workers combined, one worker leaving midway, efficiency comparisons, and pipes and cisterns with filling and emptying pipes or a leak. They are popular in PPSC, FPSC, NTS, OTS and armed forces initial tests.
Take a scored quiz instead →If 10 men can build a wall in 5 days, how long would it take 5 men?
10*5 = 5*D => D=10.
If a worker does 1/4 of work in 2 days, full work in:
2 / (1/4) = 8.
If a worker is paid 1000 for 5 days, how much for 12 days?
(1000/5) * 12 = 2400.
If 12 men or 18 women can reap a field in 14 days, how long will 8 men and 16 women take?
12M = 18W => 1M = 1.5W. 8M+16W = 12W+16W = 28W. 18W * 14 = 28W * D => D=9.
If 10 men can do a work in 15 days, in how many days can 15 men do the same work?
10 * 15 = 15 * D => D = 10.
If 6 men do a job in 8 days, how long for 4 men?
6*8 = 4*D => D=12.
If a worker does a job in 20 days and another in 30 days, together they take:
1/20 + 1/30 = 5/60 = 1/12. Time=12 days.
If 15 men can complete a work in 10 days, how many men are needed to complete it in 5 days?
15 * 10 = M * 5 => M = 150 / 5 = 30.
If a worker can complete a job in 12 days and his helper in 16 days, how long will they take working together?
1/12 + 1/16 = (4+3)/48 = 7/48. Time = 48/7 = 6.85 days.
If a tap can fill a tank in 6 hours and another can empty it in 8 hours, how long to fill if both are open?
1/6 - 1/8 = (4-3)/24 = 1/24. 24 hours.
If 15 men can do a job in 20 days, how long for 10 men?
15*20 = 10*D => D=30.
Pipe A fills in 10h, B in 20h. Together?
1/10+1/20=3/20. Time=20/3=6.66.
If 15 workers can build a wall in 48 hours, how many workers are needed to build it in 30 hours?
M1*D1 = M2*D2 => 15 * 48 = M2 * 30 => M2 = (15 * 48) / 30 = 24.
A and B can paint a house in 12 days. B alone takes 20 days. How long for A?
A+B=1/12, B=1/20. A = 1/12 - 1/20 = (5-3)/60 = 2/60 = 1/30. A = 30 days.
Tap A fills a tank in 8 hours, Tap B in 12 hours. Together?
Rate = 1/8 + 1/12 = (3+2)/24 = 5/24. Time = 4.8 hours.
12 men take 8 days. 16 men take?
12*8 = 16*D => 96=16D => D=6.
If 10 men can build a wall in 20 days, how many days will 25 men take to build the same wall?
M1 * D1 = M2 * D2 => 10 * 20 = 25 * D2 => 200 = 25 * D2 => D2 = 8.
Pipe A fills a tank in 10 hours, Pipe B in 15 hours. How long to fill together?
Rate = 1/10 + 1/15 = (3+2)/30 = 5/30 = 1/6. Time = 6 hours.
If 4 workers take 6 hours, how many hours for 8 workers?
4 * 6 = 8 * T => 24 = 8T => T = 3.
If A and B can do a piece of work in 8 days and B alone can do it in 12 days, how long will A take?
A's rate = 1/8 - 1/12 = (3 - 2) / 24 = 1/24. A takes 24 days.
Two pipes can fill a tank in 6 hours and 9 hours. How long to fill together?
Rate = 1/6 + 1/9 = (3+2)/18 = 5/18. Time = 18/5 = 3.6 hours.
If 5 machines can finish a job in 10 hours, how long for 2 machines?
5 * 10 = 2 * T => T = 50 / 2 = 25.
A can do a work in 10 days and B in 15 days. They work together for 3 days and then A leaves. How long will B take to finish the rest?
A+B=1/10+1/15=1/6. In 3 days, they do 3/6=1/2. Remaining=1/2. B does 1/2 in (1/2)/(1/15) = 7.5 days.
Two taps A and B fill a tank in 12 and 15 hours. A third pipe C can empty it in 20 hours. If all three work together, how long to fill the tank?
Rate = 1/12 + 1/15 - 1/20 = (5+4-3)/60 = 6/60 = 1/10. Time = 10 hours.
If 10 workers take 6 days to build a wall, how many days for 15 workers?
10*6 = 15*D => D = 60/15 = 4.
A and B together can do a work in 12 days. B alone can finish it in 30 days. In how many days can A alone finish the work?
A's 1-day work = (1/12) - (1/30) = (5 - 2) / 60 = 3 / 60 = 1 / 20. A takes 20 days.
Two pipes A and B can fill a cistern in 15 hours and 20 hours respectively. A third pipe C can empty it in 30 hours. If all three work together, how long to fill the cistern?
Net filling rate = 1/15 + 1/20 - 1/30 = (4 + 3 - 2) / 60 = 5 / 60 = 1 / 12 per hour. Time taken = 12 hours.
If 16 men can complete a project in 15 days, how many men are needed to complete the project in 10 days?
M1 * D1 = M2 * D2 => 16 * 15 = M2 * 10 => M2 = 240 / 10 = 24 men.
A can complete a piece of work in 20 days and B in 30 days. They work together for 5 days, and then A leaves. How many days will B take to finish the remaining work?
A's 1-day work = 1/20, B's 1-day work = 1/30. Combined 1-day work = 1/20 + 1/30 = 5/60 = 1/12. In 5 days, they complete 5/12 of the work. Remaining work = 7/12. Time taken by B = (7/12) / (1/30) = (7 * 30) / 12 = 17.5 days.
Pipe A can fill a tank in 10 hours and Pipe B can empty it in 15 hours. How long will it take to fill the tank if both pipes are opened together?
Net filling rate = 1/10 - 1/15 = (3 - 2) / 30 = 1/30 per hour. Time to fill the tank = 30 hours.
If 12 men or 15 women can finish a task in 20 days, how long will 4 men and 5 women take?
12 Men = 15 Women => 1 Man = 1.25 Women. 4 Men + 5 Women = 4(1.25) + 5 = 5 + 5 = 10 Women. Days required = (15 * 20) / 10 = 30 days.
A and B can do a job in 12 days, B and C in 15 days, C and A in 20 days. How long will A take alone to complete the job?
2(1/A + 1/B + 1/C) = 1/12 + 1/15 + 1/20 = (5 + 4 + 3) / 60 = 12/60 = 1/5 => 1/A + 1/B + 1/C = 1/10. Since 1/B + 1/C = 1/15, 1/A = 1/10 - 1/15 = 1/30. A takes 30 days.
Two pipes can fill a tank in 12 min and 15 min respectively. A third pipe empties it in 6 min. If all three operate, how long to empty a full tank?
Net emptying rate = 1/6 - (1/12 + 1/15) = 1/6 - (5+4)/60 = 10/60 - 9/60 = 1/60 per min. Time to empty full tank = 60 minutes.
If 8 men can build a wall in 12 days, how many men are required to build the same wall in 6 days?
M1 * D1 = M2 * D2 => 8 * 12 = M2 * 6 => M2 = 96 / 6 = 16 men.
A can finish a work in 12 days and B can finish it in 18 days. A works alone for 3 days and then B joins him. In how many more days will the work be completed?
A's 1-day work = 1/12, B's 1-day work = 1/18. In 3 days, A completes 3/12 = 1/4 of the work. Remaining work = 3/4. Combined 1-day work = 1/12 + 1/18 = 5/36. Remaining days = (3/4) / (5/36) = 27/5 = 5.4 days.
A pipe can fill a pool in 8 hours, but due to a leak at the bottom, it takes 10 hours. How long will the leak take to empty a full pool?
Rate of leak = 1/8 - 1/10 = (5 - 4) / 40 = 1/40 per hour. Time to empty full pool = 40 hours.
A can do a work in 15 days and B in 20 days. If they work together for 4 days, what fraction of the work is left?
A's 1-day work = 1/15, B's 1-day work = 1/20. Together in 1 day = 1/15 + 1/20 = 7/60. In 4 days = 4 * (7/60) = 7/15. Fraction left = 1 - 7/15 = 8/15.
A tank can be filled by Pipe A in 5 hours and Pipe B in 10 hours, while Pipe C empties it in 20 hours. If all three are opened together, how long to fill the tank?
Net rate = 1/5 + 1/10 - 1/20 = (4 + 2 - 1) / 20 = 5 / 20 = 1/4 per hour. Time required = 4 hours.
A, B, and C can complete a piece of work in 10, 12, and 15 days respectively. In how many days can they finish it together?
1-day work = 1/10 + 1/12 + 1/15 = (6 + 5 + 4) / 60 = 15 / 60 = 1/4. Days taken together = 4 days.
If a worker can complete 1/4 of a work in 5 days, how many days will he take to complete 3/4 of the work?
Time to complete full work = 5 * 4 = 20 days. Time for 3/4 of work = 20 * (3/4) = 15 days.
A tap can fill a tank in 6 hours, while a drain pipe can empty it in 10 hours. If both are open, how long will it take to fill the tank?
Net rate = 1/6 - 1/10 = (5 - 3) / 30 = 2 / 30 = 1/15 per hour. Time required = 15 hours.
If 5 workers can build 5 tables in 5 days, how many days will 10 workers take to build 10 tables?
Using (M1 * D1) / W1 = (M2 * D2) / W2: (5 * 5) / 5 = (10 * D2) / 10 => 5 = D2 => D2 = 5 days.
If 12 men can complete a work in 20 days, in how many days can 15 men complete the same work?
Using M1 * D1 = M2 * D2: 12 * 20 = 15 * D2 => 240 = 15 * D2 => D2 = 16 days.
A cistern has two pipes. Pipe A fills it in 8 hours and Pipe B empties it in 12 hours. If both are opened together, how long to fill the cistern?
Net rate = 1/8 - 1/12 = (3 - 2)/24 = 1/24 per hour. Time required = 24 hours.
If 15 workers can build a wall in 20 days, how many workers are needed to build the same wall in 12 days?
Using inverse proportion (M1 * D1 = M2 * D2): 15 * 20 = M2 * 12 => 300 = 12 * M2 => M2 = 25 workers.
If 12 men or 18 women can finish a task in 14 days, how long will 8 men and 6 women take to finish the same task?
12 men = 18 women => 1 man = 1.5 women. 8 men + 6 women = 8(1.5) + 6 = 18 women. Since 18 women take 14 days, 8 men and 6 women will also take 14 days.
If 8 men can complete a project in 15 days, how many days will 12 men take to complete the same project?
Using inverse proportion formula M1 * D1 = M2 * D2: 8 * 15 = 12 * D2 => 120 = 12 * D2 => D2 = 10 days.
A pipe can fill a tank in 10 hours. Due to a leak at the bottom, it takes 12 hours. How long will the leak take to empty the full tank?
Leak's rate per hour = 1/10 - 1/12 = (6 - 5)/60 = 1/60. Time taken by leak alone = 60 hours.
If A can do a job in 10 days and B can do it in 15 days, how many days will they take working together?
Combined rate = 1/10 + 1/15 = 5/30 = 1/6. Days taken together = 6 days.
If a work is completed by 8 workers in 12 days, how many extra workers are needed to finish it in 8 days?
Workers needed = (8 * 12) / 8 = 12 workers. Extra workers required = 12 - 8 = 4 workers.
If 12 workers can complete a project in 15 days, how many days will 10 workers take to complete the same work at the same rate?
Work done is inversely proportional to the number of workers: Workers × Days = Constant. Therefore, 12 × 15 = 10 × Days. Days = 180 / 10 = 18 days.
If 12 workers can build a wall in 8 days, how many workers are needed to complete it in 6 days?
M1 * D1 = M2 * D2 => 12 * 8 = M2 * 6 => 96 = 6 * M2 => M2 = 16 workers.
If 8 men can complete a job in 12 days, how many days will 6 men take to finish the same job?
M1 * D1 = M2 * D2 => 8 * 12 = 6 * D2 => 96 = 6 * D2 => D2 = 16 days.
A tap fills a tank in 4 hours and a drain empties it in 6 hours. If both are open, how long to fill the empty tank?
Net rate per hour = 1/4 - 1/6 = (3 - 2) / 12 = 1/12. Time required = 12 hours.
Pipe A can fill a tank in 6 hours and Pipe B can empty it in 12 hours. How long will it take to fill the tank if both are open?
Net work rate per hour = 1/6 - 1/12 = 1/12. Time required = 12 hours.
A, B, and C can complete a job in 10 days working together. A alone takes 30 days and B alone takes 20 days. How long will C take alone?
C's rate = Combined rate - (A's rate + B's rate) = 1/10 - (1/30 + 1/20) = 1/10 - 5/60 = 1/60 per day. C takes 60 days.