SSC Time and Work Questions with Solutions and Tricks

Time and Work is one of the most scoring chapters in SSC Quantitative Aptitude. Two to four questions come from it in almost every shift of CGL, CHSL, MTS and GD, and with the LCM (total work) method you can solve most of them in under 40 seconds. This practice paper gives you 30 carefully graded questions with answers and short solutions, so you can learn the shortcut and build speed at the same time.

Practice Paper at a Glance

What Is Time and Work? Basic Concept in Simple Words

Every time and work question is built on one idea: Work = Rate of work x Time. If a person finishes a job in 10 days, his one-day work is 1/10 of the job. The more people (or the more efficient they are), the less time the job takes.

• One day work = 1 / (days taken). If A takes 12 days, A does 1/12 of the work per day.
• Together: add the one-day work of everyone working at the same time.
• Efficiency is the amount of work done in one day. More efficiency means fewer days, so efficiency is inversely proportional to time.
• Man-days: work is proportional to (men x days x hours per day).

Formulas and Shortcut Tricks for SSC Time and Work

• Two people: if A takes a days and B takes b days, together they take ab / (a + b) days.
• LCM method: take the LCM of all the given days as the total work. Divide it by each person's days to get daily efficiency. Add the efficiencies and divide the total work by the sum.
• Man-days formula: (M1 x D1 x H1) / W1 = (M2 x D2 x H2) / W2.
• Efficiency ratio: if A is twice as efficient as B, A takes half the days. Efficiency ratio is the reverse of the time ratio.
• Wages are shared in the ratio of work done (efficiency x days worked).
• Pipes and cisterns: an inlet pipe is positive work, an outlet pipe is negative work. Use the same LCM method.
• If A+B, B+C and C+A are given: add all three one-day works and divide by 2 to get A+B+C.
• Alternate days: find the work done in one full cycle (2 days), count the full cycles, then handle the leftover.

Set 1: Basic Time and Work Questions (Q1–Q10)

Q1. A can do a piece of work in 12 days. How much work does A do in 1 day?
Answer: 1/12 of the work
Solution: One day work = 1 / (total days) = 1/12.

Q2. A can finish a work in 10 days and B can finish it in 15 days. In how many days will they finish it working together?
Answer: 6 days
Trick: LCM of 10 and 15 = 30. A = 3 units/day, B = 2 units/day. Together 5 units/day, so 30 / 5 = 6 days.

Q3. A can do a work in 20 days and B in 30 days. How long will they take together?
Answer: 12 days
Trick: Using ab/(a+b): (20 x 30) / 50 = 12 days.

Q4. A and B together can finish a work in 8 days. A alone can finish it in 12 days. In how many days can B alone finish it?
Answer: 24 days
Solution: Take total work = 24 units. Together = 3 units/day, A = 2 units/day, so B = 1 unit/day. B alone takes 24 days.

Q5. A can do a work in 15 days. He works for 5 days and leaves. What part of the work is left?
Answer: 2/3
Solution: Work done = 5/15 = 1/3. Work left = 1 - 1/3 = 2/3.

Q6. 6 men can complete a work in 10 days. In how many days can 1 man complete it?
Answer: 60 days
Solution: Total work = 6 x 10 = 60 man-days, so 1 man needs 60 days.

Q7. 8 men can build a wall in 12 days. How many days will 6 men take to build the same wall?
Answer: 16 days
Solution: Man-days = 8 x 12 = 96. Days for 6 men = 96 / 6 = 16.

Q8. A is twice as efficient as B. Together they finish a work in 12 days. In how many days can A alone finish it?
Answer: 18 days
Solution: Efficiency A : B = 2 : 1. Total work = 12 x 3 = 36 units. A does 2 units/day, so 36 / 2 = 18 days.

Q9. A can do a work in 9 days and B in 18 days. In how many days will they finish it together?
Answer: 6 days
Solution: LCM = 18. A = 2, B = 1 per day. Together 3 per day, so 18 / 3 = 6 days.

Q10. A can complete a job in 25 days and B in 20 days. How many days will they take working together?
Answer: 11 1/9 days (100/9)
Solution: LCM = 100. A = 4, B = 5 per day. Together 9 per day, so 100 / 9 = 11 1/9 days.

Set 2: Efficiency, Leaving and Joining Questions (Q11–Q20)

Q11. A can do a work in 10 days and B in 15 days. They work together for 4 days and then A leaves. In how many more days will B finish the remaining work?
Answer: 5 days
Solution: LCM = 30. A = 3, B = 2. In 4 days they do 4 x 5 = 20 units. Remaining 10 units at 2 per day = 5 days.

Q12. A and B can do a work in 12 days, B and C in 15 days, C and A in 20 days. In how many days can all three together do it?
Answer: 10 days
Trick: Add: 1/12 + 1/15 + 1/20 = 12/60 = 1/5. That equals 2(A+B+C), so A+B+C = 1/10. Time = 10 days.

Q13. A is 50% more efficient than B. If B alone can do a work in 30 days, in how many days can A alone do it?
Answer: 20 days
Solution: Efficiency A : B = 3 : 2, so time A : B = 2 : 3. A takes 2/3 x 30 = 20 days.

Q14. A is 25% more efficient than B. Together they finish a work in 20 days. In how many days can B alone finish it?
Answer: 45 days
Solution: Efficiency A : B = 5 : 4. Total work = 20 x 9 = 180 units. B does 4 units/day, so 180 / 4 = 45 days.

Q15. A can do a work in 24 days. B is three times as efficient as A. In how many days will they complete it together?
Answer: 6 days
Solution: B takes 24 / 3 = 8 days. Together: (24 x 8) / (24 + 8) = 6 days.

Q16. A and B together can do a work in 18 days. B alone can do it in 30 days. In how many days can A alone do it?
Answer: 45 days
Solution: LCM = 90. Together = 5, B = 3, so A = 2 per day. A alone takes 90 / 2 = 45 days.

Q17. 15 men can complete a work in 20 days. After 5 days, 5 men leave. In how many days in all will the work be completed?
Answer: 27.5 days
Solution: Total = 15 x 20 = 300 man-days. In 5 days they finish 75. Left = 225 man-days with 10 men = 22.5 days. Total = 5 + 22.5 = 27.5 days.

Q18. 12 men can finish a work in 18 days. How many more men are needed to finish it in 9 days?
Answer: 12 more men
Solution: Total = 12 x 18 = 216 man-days. Men needed for 9 days = 216 / 9 = 24. Extra men = 24 - 12 = 12.

Q19. A worked alone for 3 days (A can finish the whole work in 10 days) and then B completed the rest in 7 days. In how many days can B alone finish the whole work?
Answer: 10 days
Solution: A does 3/10 of the work. Remaining 7/10 is done by B in 7 days, so B does 1/10 per day. B alone takes 10 days.

Q20. A and B can do a work in 20 and 30 days. They start together, but A leaves 5 days before the work is completed. In how many days is the work finished?
Answer: 15 days
Solution: Let total time = t. B works t days and A works (t - 5) days. (t - 5)/20 + t/30 = 1. Multiply by 60: 3(t - 5) + 2t = 60, so 5t = 75 and t = 15.

Set 3: Wages, Pipes, Alternate Days and Mixed Questions (Q21–Q30)

Q21. A and B can do a job in 10 and 15 days. They are paid Rs 1,500 for finishing it together. What is the share of A?
Answer: Rs 900
Solution: Work ratio when working together = 1/10 : 1/15 = 3 : 2. A's share = 3/5 x 1,500 = Rs 900.

Q22. A, B and C can finish a work in 12, 24 and 8 days. They finish it together and get Rs 4,800. How much does C get?
Answer: Rs 2,400
Solution: LCM = 24. Efficiencies A : B : C = 2 : 1 : 3. C's share = 3/6 x 4,800 = Rs 2,400.

Q23. Pipe A can fill a tank in 20 minutes and pipe B in 30 minutes. If both are opened together, in how much time will the tank be full?
Answer: 12 minutes
Solution: LCM = 60. A = 3, B = 2 per minute. Together 5, so 60 / 5 = 12 minutes.

Q24. An inlet pipe can fill a tank in 12 hours and an outlet pipe can empty the full tank in 18 hours. If both are opened together, in how many hours will the empty tank be filled?
Answer: 36 hours
Solution: LCM = 36. Inlet = +3, outlet = -2 per hour. Net 1 per hour, so the tank fills in 36 hours.

Q25. Pipe A can fill a tank in 6 hours and pipe B in 8 hours. If both are opened together, in how many hours will the tank be full?
Answer: 3 3/7 hours (24/7)
Solution: LCM = 24. A = 4, B = 3 per hour. Together 7, so 24 / 7 = 3 3/7 hours.

Q26. A can do a work in 10 days and B in 15 days. They work on alternate days, starting with A. In how many days will the work be completed?
Answer: 12 days
Solution: LCM = 30. A = 3, B = 2. In 2 days (one cycle) they do 5 units. 6 cycles = 12 days = 30 units. Work finishes in 12 days.

Q27. A can do a work in 12 days and B in 18 days. They work on alternate days, starting with A. In how many days will the work be completed?
Answer: 14 1/3 days
Solution: LCM = 36. A = 3, B = 2. One cycle = 5 units in 2 days. 7 cycles = 14 days = 35 units. Remaining 1 unit is done by A on day 15 in 1/3 day. Total 14 1/3 days.

Q28. A and B together can finish a work in 10 days. A alone can finish it in 16 days. In how many days can B alone finish it?
Answer: 26 2/3 days (80/3)
Solution: LCM = 80. Together = 8, A = 5, so B = 3 per day. B alone takes 80 / 3 = 26 2/3 days.

Q29. 20 men can build a wall in 15 days working 8 hours a day. In how many days can 25 men build it working 6 hours a day?
Answer: 16 days
Solution: Total = 20 x 15 x 8 = 2,400 man-hours. Per day 25 x 6 = 150. Days = 2,400 / 150 = 16.

Q30. A and B can do a work in 6 days, B and C in 8 days and A and C in 12 days. In how many days can all three finish it together?
Answer: 5 1/3 days (16/3)
Trick: Add: 1/6 + 1/8 + 1/12 = 9/24 = 3/8. This is 2(A+B+C), so A+B+C = 3/16. Time = 16/3 = 5 1/3 days.

Common Mistakes in Time and Work Questions

• Adding the number of days instead of adding the one-day work.
• Forgetting to convert "more efficient" into an efficiency ratio and then reversing it for time.
• Treating the leftover work as a full day in alternate-day problems.
• Using the man-days formula without including hours per day when hours are given.
• Dividing wages equally instead of in the ratio of work done.
• Not checking the units: days, hours or minutes should match in pipe problems.

How to Practice These 30 Questions

1. Read the formulas and tricks section once and write them in your notebook.
2. Attempt each set in a timer: Set 1 in 8 minutes, Set 2 in 12 minutes and Set 3 in 15 minutes.
3. Always try the LCM method first before using fractions.
4. Check your answers and re-solve the questions you got wrong after 24 hours.
5. Repeat the full paper after a week and try to reduce your total time.

Related Topics to Study Next

• SSC Percentage Questions
• Time, Speed and Distance Questions
• Ratio and Proportion Questions
• SSC Previous Year Papers

Frequently Asked Questions

What is time and work in SSC maths?

Time and work is a Quantitative Aptitude chapter in which you find the time taken, the work done or the number of workers when one or more people or machines complete a job. The key idea is Work = Rate x Time.

What is the formula for time and work?

If A completes a work in a days and B in b days, their combined time is ab / (a + b) days. The general formula is Work = Efficiency x Time. For groups, use (M1 x D1 x H1) / W1 = (M2 x D2 x H2) / W2.

What is the LCM method in time and work?

Take the LCM of the days given as the total work in units. Divide it by each person's days to find daily units. Add the units of those working together and divide the total work by it to get the time.

How many time and work questions come in SSC CGL Tier 1?

Usually two to four questions per shift come from time and work, pipes and cisterns and related topics. It is a high-scoring and predictable topic.

How is wage divided in time and work questions?

Wages are divided in the ratio of the work done, which is efficiency multiplied by the number of days worked. If people work for the same number of days, the ratio is simply the ratio of their efficiencies.

What is the difference between efficiency and time?

Efficiency is the amount of work done in a unit of time, while time is the number of days needed for the complete work. They are inversely related: if efficiency doubles, time becomes half.

How do I solve pipes and cisterns questions quickly?

Use the same LCM method. Treat inlet pipes as positive efficiency and outlet pipes or leaks as negative efficiency, add them and divide the capacity by the net rate.

How do I solve alternate day work questions?

Find the work done in one full cycle (for example A on day 1 and B on day 2). Divide total work by this to count full cycles, then handle the remaining work on the next day of the person whose turn it is.

What is the man-days concept?

Man-days is the total work expressed as the number of men multiplied by the number of days. For the same work, men x days stays constant, so more men need fewer days.

How should I practice time and work for SSC exams?

Learn the LCM method, solve one set daily in a fixed time, review mistakes and finish with previous year SSC papers. Also practise percentage and ratio, because many time and work problems use them.