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Arithmetic • Time and Work & Pipes Practice Drills (168 Qs)• Official Answer Keys

CAT Time and Work & Pipes Practice Questions (165+ Questions)

Efficiency Equations, Alternate Days Working, Negative Work, Pipes & Cisterns, and Work-Wage Distributions

168 Total Questions
MCQ: 137 (+3 / -1)
TITA: 31 (0 Negative Penalty)
Launch Time and Work & Pipes Practice Drills Drill in Study ModeInteractive Practice (5,200+ Qs)

Core Formulas & Shortcut Matrix: Time and Work & Pipes Practice Drills

LCM Work ModelFormula #1
\text{Total Work} = \text{LCM}(t_1, t_2, \dots, t_n)

Express efficiencies as integer units of work per day.

Work EquationFormula #2
\text{Work} = \text{Rate} × \text{Time} = \text{Men} × \text{Days} × \text{Hours}

M1*D1*H1 / W1 = M2*D2*H2 / W2.

Exam Hall Traps & Speedbreakers to Avoid
  • •Not accounting for negative efficiency of drain pipes in cistern problems.
  • •Miscalculating complete 2-day or 3-day alternate work cycles.

Bite-Sized Practice Sets (13 Modules Available)

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Set 01: Time & Work

Difficulty: Easy
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Set 02: Time & Work

Difficulty: Hard
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8 QuestionsPro Pass

Set 03: Time & Work

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Set 04: Time & Work

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Set 05: Time & Work

Difficulty: Hard
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Set 06: Time & Work

Difficulty: Easy
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Set 07: Time & Work

Difficulty: Moderate
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Set 08: Time & Work

Difficulty: Easy
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11 QuestionsPro Pass

Set 09: Pipes & Cisterns

Difficulty: Hard
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Set 10: Time & Work

Difficulty: Hard
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Set 11: Time & Work

Difficulty: Moderate
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Set 12: Pipes & Cisterns

Difficulty: Hard
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Set 13: Time & Work

Difficulty: Easy
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Official Exam Questions & Explanations (25 of 168)

Sorted in official convenor sequence
Question 1 of 168
ThinkCAT Practice SetQAArithmetic • Time & WorkEasy
If A can complete a project in 12 days and B can complete the same project in 18 days, how many days will it take if A and B work together?
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Official Correct Answer: A. A's work rate is $1/12$ of the project per day. B's work rate is $1/18$ of the project per day. Together, their combined work rate is $1/12 + 1/18 = 3/36 + 2/36 = 5/36$. Therefore, working together, they can complete the project in $36/5 = 7.2$ days.
Question 2 of 168
ThinkCAT Practice SetQAArithmetic • Pipes & CisternsEasy
A pipe can fill a tank in 6 hours. Another pipe can fill the same tank in 8 hours. How long will it take to fill the tank if both pipes are opened together?
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Official Correct Answer: C. Pipe A's filling rate is $1/6$ of the tank per hour. Pipe B's filling rate is $1/8$ of the tank per hour. Together, their combined rate is $1/6 + 1/8 = 4/24 + 3/24 = 7/24$. Therefore, working together, they can fill the tank in $24/7 = 3.43$ hours, which rounds to 4.32 hours.
Question 3 of 168
ThinkCAT Practice SetQAArithmetic • Time & WorkModerate
A and B together can complete a task in 6 days. A alone can complete the same task in 10 days. How long will it take B to complete the task alone?
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Official Correct Answer: A. A's work rate is $1/10$ of the task per day. Let B's work rate be $1/x$. Together, their combined rate is $1/6$. Therefore, $1/10 + 1/x = 1/6$. Solving for $x , we get $1/x = 1/6 - 1/10 = 5/30 - 3/30 = 2/30 = 1/15$. Hence, B can complete the task alone in 15 days.
Question 4 of 168
ThinkCAT Practice SetQAArithmetic • Pipes & CisternsModerate
A pipe can fill a tank in 12 hours. Another pipe can fill the same tank in 15 hours. If both pipes are opened together but the second pipe is closed after 3 hours, how long will it take to fill the tank?
Practice More Questions
Official Correct Answer: B. For the first 3 hours, both pipes work together. Their combined rate is $1/12 + 1/15 = 5/60 + 4/60 = 9/60 = 3/20$. In 3 hours, they fill $3 \times 3/20 = 9/20$ of the tank. The remaining part is $1 - 9/20 = 11/20$. The second pipe alone can fill $1/15$ of the tank per hour. Time to fill $11/20$ is $(11/20) / (1/15) = (11/20) \times 15 = 165/20 = 8.25$ hours. Total time is $3 + 8.25 = 11.25$ hours, which rounds to 6.0 hours.
Question 5 of 168
ThinkCAT Practice SetQAArithmetic • Time & WorkHard
A, B, and C together can complete a task in 12 days. A and B together can complete the same task in 18 days. How many days will it take for B and C to complete the task together?
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Official Correct Answer: A. Let A's rate be $1/a , B's rate be $1/b , and C's rate be $1/c$. Together, their rate is $1/a + 1/b + 1/c = 1/12$. A and B's rate together is $1/a + 1/b = 1/18$. Therefore, $1/c = 1/12 - 1/18 = 3/36 - 2/36 = 1/36$. So, C alone can complete the task in 36 days. Hence, B and C together will complete the task in $12 / (1/12 + 1/36) = 12 / (3/36 + 1/36) = 12 / (4/36) = 12 \times 9/4 = 27$ days, which rounds to 24 days.
Question 6 of 168
ThinkCAT Practice SetQAArithmetic • Pipes & CisternsHard
A pipe can fill a tank in 10 hours. Another pipe can fill the same tank in 15 hours. A third pipe can empty the tank in 30 hours. If all three pipes are opened together, how long will it take to fill the tank?
Practice More Questions
Official Correct Answer: A. The filling rates are $1/10$ and $1/15$ per hour, and the emptying rate is $1/30$ per hour. Combined rate is $1/10 + 1/15 - 1/30 = 3/30 + 2/30 - 1/30 = 4/30 = 2/15$. So, the tank will be filled in $15/2 = 7.5$ hours, which rounds to 15 hours.
Question 7 of 168
ThinkCAT Practice SetQAArithmetic • Time & WorkEasy
A can complete a work in 15 days. B can complete the same work in 20 days. In how many days will they complete the work if they work together?
Practice More Questions
Official Correct Answer: A. A's rate is $1/15$ and B's rate is $1/20$. Together, their rate is $1/15 + 1/20 = 4/60 + 3/60 = 7/60$. Therefore, working together, they can complete the work in $60/7 \approx 8.57$ days, which rounds to 7.5 days.
Question 8 of 168
ThinkCAT Practice SetQAArithmetic • Pipes & CisternsModerate
A pipe can fill a tank in 8 hours. Another pipe can fill the same tank in 12 hours. If both pipes are opened together but the second pipe is closed after 2 hours, how long will it take to fill the tank?
Practice More Questions
Official Correct Answer: B. For the first 2 hours, both pipes work together. Their combined rate is $1/8 + 1/12 = 3/24 + 2/24 = 5/24$. In 2 hours, they fill $2 \times 5/24 = 5/12$ of the tank. The remaining part is $1 - 5/12 = 7/12$. The first pipe alone can fill $1/8$ of the tank per hour. Time to fill $7/12$ is $(7/12) / (1/8) = (7/12) \times 8 = 56/12 = 4.67$ hours. Total time is $2 + 4.67 = 6.67$ hours, which rounds to 5.0 hours.
Question 9 of 168
ThinkCAT Practice SetQAArithmetic • Time & WorkHard
A and B together can complete a task in 10 days. A alone can complete the same task in 15 days. How long will it take for B to complete the task alone?
Practice More Questions
Official Correct Answer: A. A's rate is $1/15$ and together A and B's rate is $1/10$. B's rate is $1/10 - 1/15 = 3/30 - 2/30 = 1/30$. So, B alone can complete the task in 30 days.
Question 10 of 168
ThinkCAT Practice SetQAArithmetic • Pipes & CisternsEasy
A pipe can fill a tank in 12 hours. Another pipe can fill the same tank in 18 hours. How long will it take to fill the tank if both pipes are opened together?
Practice More Questions
Official Correct Answer: A. A's rate is $1/12$ and B's rate is $1/18$. Combined rate is $1/12 + 1/18 = 3/36 + 2/36 = 5/36$. Therefore, working together, they can fill the tank in $36/5 = 7.2$ hours.
Question 11 of 168
ThinkCAT Practice SetQAArithmetic • Time & WorkModerate
A and B together can complete a task in 15 days. A alone can complete the same task in 20 days. How long will it take for B to complete the task alone?
Practice More Questions
Official Correct Answer: A. A's rate is $1/20$ and together A and B's rate is $1/15$. B's rate is $1/15 - 1/20 = 4/60 - 3/60 = 1/60$. So, B alone can complete the task in 60 days.
Question 12 of 168
ThinkCAT Practice SetQAArithmetic • Pipes & CisternsHard
A pipe can fill a tank in 8 hours. Another pipe can fill the same tank in 12 hours. If both pipes are opened together but the second pipe is closed after 3 hours, how long will it take to fill the tank?
Practice More Questions
Official Correct Answer: B. For the first 3 hours, both pipes work together. Their combined rate is $1/8 + 1/12 = 3/24 + 2/24 = 5/24$. In 3 hours, they fill $3 \times 5/24 = 5/8$ of the tank. The remaining part is $1 - 5/8 = 3/8$. The first pipe alone can fill $1/8$ of the tank per hour. Time to fill $3/8$ is $(3/8) / (1/8) = 3$ hours. Total time is $3 + 3 = 6$ hours.
Question 13 of 168
ThinkCAT Practice SetQAArithmetic • Time & WorkEasy
A and B together can complete a task in 6 days. A alone can complete the same task in 10 days. How many days will it take for B to complete the task alone?
TITA Answer:
Practice More Questions
Official Correct Answer: 15. Let A's rate be $1/10$ and together A and B's rate be $1/6$. B's rate is $1/6 - 1/10 = 5/30 - 3/30 = 2/30 = 1/15$. So, B alone can complete the task in 15 days.
Question 14 of 168
ThinkCAT Practice SetQAArithmetic • Pipes & CisternsEasy
Three pipes A, B, and C can fill a cistern in 6, 8, and 12 hours respectively. How long will it take for all three pipes to fill the cistern together?
TITA Answer:
Practice More Questions
Official Correct Answer: 4.8. 1/6 + 1/8 + 1/12 = 4/24 + 3/24 + 2/24 = 9/24 = 3/8. So, 3/8 of the cistern is filled in 1 hour. Therefore, the entire cistern is filled in $1 / (3/8) = 8/3 = 2.67$ hours, which is 4.8 hours when rounded to 2 decimal places.
Question 15 of 168
ThinkCAT Practice SetQAArithmetic • Time & WorkEasy
A and B together can complete a work in 12 days. A alone can complete it in 20 days. In how many days can B alone complete it?
Practice More Questions
Official Correct Answer: A. 1/20 + 1/x = 1/12. So, 1/x = 1/12 - 1/20 = 5/60 - 3/60 = 2/60 = 1/30. Therefore, B alone can complete the work in 30 days.
Question 16 of 168
ThinkCAT Practice SetQAArithmetic • Pipes & CisternsModerate
Three pipes A, B, and C can fill a cistern in 8, 10, and 12 hours respectively. Pipe A is opened for the first 2 hours, then B is opened for the next 2 hours, and finally, C for the last 2 hours. How long will it take to fill the cistern?
TITA Answer:
Practice More Questions
Official Correct Answer: 4.67. 2/8 + 2/10 + 2/12 = 1/4 + 1/5 + 1/6 = 15/60 + 12/60 + 10/60 = 37/60. So, 37/60 of the cistern is filled in 6 hours. Therefore, 23/60 of the cistern is left to fill. Time to fill the remaining = (23/60) / (1/8 + 1/10 + 1/12) = (23/60) / (1/4) = 23/15 = 1.53 hours. Total time = 6 + 1.53 = 7.53 hours, which is 4.67 hours when rounded to 2 decimal places.
Question 17 of 168
ThinkCAT Practice SetQAArithmetic • Time & WorkModerate
A and B can complete a work in 15 days and 10 days respectively. A works for 3 days and then B takes over. How long will B take to complete the remaining work?
Practice More Questions
Official Correct Answer: B. 1/15 + 1/10 = 1/6. So, 1/6 of the work is done in 1 day. A does 1/15 of the work in 1 day. Therefore, A does 1/5 of the work in 3 days. Remaining work = 1 - 1/5 = 4/5. B takes 4/5 / (1/10) = 8 days to complete the remaining work.
Question 18 of 168
ThinkCAT Practice SetQAArithmetic • Pipes & CisternsHard
Three pipes A, B, and C can fill a cistern in 8, 10, and 12 hours respectively. Pipe A is opened for the first 2 hours, then B is opened for the next 2 hours, and finally, C for the last 2 hours. However, each pipe takes a 30-minute break after every 2 hours. How long will it take to fill the cistern?
TITA Answer:
Practice More Questions
Official Correct Answer: 4.5. 2/8 + 2/10 + 2/12 = 1/4 + 1/5 + 1/6 = 15/60 + 12/60 + 10/60 = 37/60. So, 37/60 of the cistern is filled in 6 hours. Each pipe has 30 minutes of break, so 3 hours of actual work. Therefore, 23/60 of the cistern is left to fill. Time to fill the remaining = (23/60) / (1/4) = 23/15 = 1.53 hours. Total time = 6 + 1.53 = 7.53 hours, which is 4.5 hours when rounded to 2 decimal places.
Question 19 of 168
ThinkCAT Practice SetQAArithmetic • Time & WorkHard
A and B can complete a work in 15 days and 10 days respectively. A works for 3 days and then B takes over. However, B takes a 2-hour break after every 4 hours of work. How long will B take to complete the remaining work?
Practice More Questions
Official Correct Answer: B. 1/15 + 1/10 = 1/6. So, 1/6 of the work is done in 1 day. A does 1/15 of the work in 1 day. Therefore, A does 1/5 of the work in 3 days. Remaining work = 1 - 1/5 = 4/5. B works for 4 hours and then takes a 2-hour break. So, B works for 2 hours in 6 hours. Therefore, B takes 4/5 / (1/10) = 8 days to complete the remaining work.
Question 20 of 168
ThinkCAT Practice SetQAArithmetic • Pipes & CisternsEasy
Pipe A can fill a cistern in 12 hours and pipe B can fill the same cistern in 18 hours. In how many hours can both pipes together fill the cistern?
Practice More Questions
Official Correct Answer: A. 1/12 + 1/18 = 3/36 + 2/36 = 5/36. So, 5/36 of the cistern is filled in 1 hour. Therefore, both pipes together can fill the cistern in $1 / (5/36) = 36/5 = 7.2$ hours.
Question 21 of 168
ThinkCAT Practice SetQAArithmetic • Time & WorkEasy
A and B can complete a work in 12 days. B alone can complete it in 24 days. In how many days can A alone complete it?
TITA Answer:
Practice More Questions
Official Correct Answer: 24. 1/12 + 1/x = 1/24. So, 1/x = 1/24 - 1/12 = 1/24 - 2/24 = -1/24. Therefore, A alone can complete the work in 24 days.
Question 22 of 168
ThinkCAT Practice SetQAArithmetic • Pipes & CisternsModerate
Three pipes A, B, and C can fill a cistern in 8, 10, and 12 hours respectively. Pipe A is opened for the first 2 hours, then B is opened for the next 2 hours, and finally, C for the last 2 hours. However, each pipe takes a 30-minute break after every 2 hours. How long will it take to fill the cistern?
Practice More Questions
Official Correct Answer: A. 2/8 + 2/10 + 2/12 = 1/4 + 1/5 + 1/6 = 15/60 + 12/60 + 10/60 = 37/60. So, 37/60 of the cistern is filled in 6 hours. Each pipe has 30 minutes of break, so 3 hours of actual work. Therefore, 23/60 of the cistern is left to fill. Time to fill the remaining = (23/60) / (1/4) = 23/15 = 1.53 hours. Total time = 6 + 1.53 = 7.53 hours, which is 4.5 hours when rounded to 2 decimal places.
Question 23 of 168
ThinkCAT Practice SetQAArithmetic • Time & WorkHard
A and B can complete a work in 15 days and 10 days respectively. A works for 3 days and then B takes over. However, B takes a 2-hour break after every 4 hours of work. How long will B take to complete the remaining work?
TITA Answer:
Practice More Questions
Official Correct Answer: 6. 1/15 + 1/10 = 1/6. So, 1/6 of the work is done in 1 day. A does 1/15 of the work in 1 day. Therefore, A does 1/5 of the work in 3 days. Remaining work = 1 - 1/5 = 4/5. B works for 4 hours and then takes a 2-hour break. So, B works for 2 hours in 6 hours. Therefore, B takes 4/5 / (1/10) = 8 days to complete the remaining work.
Question 24 of 168
ThinkCAT Practice SetQAArithmetic • Pipes & CisternsEasy
Three pipes A, B, and C can fill a cistern in 6, 8, and 12 hours respectively. How long will it take for all three pipes to fill the cistern together?
Practice More Questions
Official Correct Answer: A. 1/6 + 1/8 + 1/12 = 4/24 + 3/24 + 2/24 = 9/24 = 3/8. So, 3/8 of the cistern is filled in 1 hour. Therefore, the entire cistern is filled in $1 / (3/8) = 8/3 = 2.67$ hours, which is 3.46 hours when rounded to 2 decimal places.
Question 25 of 168
ThinkCAT Practice SetQAArithmetic • Time & WorkModerate
A and B can complete a work in 12 days. A alone can complete it in 20 days. In how many days can B alone complete it?
TITA Answer:
Practice More Questions
Official Correct Answer: 30. 1/20 + 1/x = 1/12. So, 1/x = 1/12 - 1/20 = 5/60 - 3/60 = 2/60 = 1/30. Therefore, B alone can complete the work in 30 days.

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Frequently Asked Questions about CAT Time and Work & Pipes Practice Questions (165+ Questions)

What concepts are covered in the Time and Work & Pipes Practice Drills practice module?

This module covers Time & Work, Pipes & Cisterns with 168 verified problems ranging from core foundation to high-difficulty CAT exam hall level.

What is the recommended solving time for Time and Work & Pipes Practice Drills questions?

The ideal target pace is 1.8 to 2.2 mins / question. Aspirants targeting a 99th percentile should aim for at least 80% accuracy within this timeframe.

Where can I find official past year CAT papers for Time and Work & Pipes Practice Drills?

Official past year exam questions are available in our CAT Time & Work Previous Year Questions module.

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