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UPSC Civil Services Time & Work Questions with Answers & Explanations

18 Time & Work questions from the Basic Numeracy & Data Interpretation section of UPSC Civil Services, each with the correct answer and a worked explanation. Try each question first, then tap Show answer to check. When you're ready, take the timed chapter-wise test to see your all-India rank.

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Question 1

A can complete a work in 15 days and B can complete it in 30 days. In how many days can they complete it working together?

  1. A22.5 days
  2. B12 days
  3. C9 days
  4. D10 days
Show answer
Answer: (D) 10 days Together they do 1/15 + 1/30 = 1/10 of the work per day, so 10 days.
Question 2

Pipe A can fill a tank in 9 hours and pipe B can empty it in 12 hours. If both are opened together, in how many hours will the empty tank be filled?

  1. A5.1428571428571 hours
  2. B41 hours
  3. C36 hours
  4. D3 hours
Show answer
Answer: (C) 36 hours Net filling per hour = 1/9 − 1/12 = 1/36, so 36 hours.
Question 3

A can complete a work in 20 days and B can complete it in 80 days. In how many days can they complete it working together?

  1. A20 days
  2. B15 days
  3. C16 days
  4. D50 days
Show answer
Answer: (C) 16 days Together they do 1/20 + 1/80 = 1/16 of the work per day, so 16 days.
Question 4

Pipe A can fill a tank in 10 hours and pipe B can empty it in 15 hours. If both are opened together, in how many hours will the empty tank be filled?

  1. A6 hours
  2. B30 hours
  3. C5 hours
  4. D35 hours
Show answer
Answer: (B) 30 hours Net filling per hour = 1/10 − 1/15 = 1/30, so 30 hours.
Question 5

A can complete a work in 20 days and B can complete it in 30 days. In how many days can they complete it working together?

  1. A12 days
  2. B14 days
  3. C25 days
  4. D16 days
Show answer
Answer: (A) 12 days Together they do 1/20 + 1/30 = 1/12 of the work per day, so 12 days.
Question 6

Pipe A can fill a tank in 20 hours and pipe B can empty it in 30 hours. If both are opened together, in how many hours will the empty tank be filled?

  1. A57 hours
  2. B12 hours
  3. C60 hours
  4. D65 hours
Show answer
Answer: (C) 60 hours Net filling per hour = 1/20 − 1/30 = 1/60, so 60 hours.
Question 7

A can complete a work in 10 days and B can complete it in 40 days. In how many days can they complete it working together?

  1. A10 days
  2. B7 days
  3. C25 days
  4. D8 days
Show answer
Answer: (D) 8 days Together they do 1/10 + 1/40 = 1/8 of the work per day, so 8 days.
Question 8

Pipe A can fill a tank in 12 hours and pipe B can empty it in 20 hours. If both are opened together, in how many hours will the empty tank be filled?

  1. A30 hours
  2. B8 hours
  3. C7.5 hours
  4. D35 hours
Show answer
Answer: (A) 30 hours Net filling per hour = 1/12 − 1/20 = 1/30, so 30 hours.
Question 9

A can complete a work in 24 days and B can complete it in 40 days. In how many days can they complete it working together?

  1. A17 days
  2. B15 days
  3. C19 days
  4. D32 days
Show answer
Answer: (B) 15 days Together they do 1/24 + 1/40 = 1/15 of the work per day, so 15 days.
Question 10

A can complete a work in 15 days and B can complete it in 30 days. In how many days can they complete it working together?

  1. A9 days
  2. B12 days
  3. C10 days
  4. D22.5 days
Show answer
Answer: (C) 10 days Together they do 1/15 + 1/30 = 1/10 of the work per day, so 10 days.

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Question 11

Pipe A can fill a tank in 15 hours and pipe B can empty it in 20 hours. If both are opened together, in how many hours will the empty tank be filled?

  1. A60 hours
  2. B5 hours
  3. C65 hours
  4. D8.5714285714286 hours
Show answer
Answer: (A) 60 hours Net filling per hour = 1/15 − 1/20 = 1/60, so 60 hours.
Question 12

A can complete a work in 21 days and B can complete it in 42 days. In how many days can they complete it working together?

  1. A31.5 days
  2. B14 days
  3. C18 days
  4. D16 days
Show answer
Answer: (B) 14 days Together they do 1/21 + 1/42 = 1/14 of the work per day, so 14 days.
Question 13

A can complete a work in 30 days and B can complete it in 60 days. In how many days can they complete it working together?

  1. A20 days
  2. B24 days
  3. C22 days
  4. D45 days
Show answer
Answer: (A) 20 days Together they do 1/30 + 1/60 = 1/20 of the work per day, so 20 days.
Question 14

A can complete a work in 6 days and B can complete it in 12 days. In how many days can they complete it working together?

  1. A4 days
  2. B6 days
  3. C3 days
  4. D8 days
Show answer
Answer: (A) 4 days Together they do 1/6 + 1/12 = 1/4 of the work per day, so 4 days.
Question 15

Pipe A can fill a tank in 8 hours and pipe B can empty it in 12 hours. If both are opened together, in how many hours will the empty tank be filled?

  1. A4.8 hours
  2. B4 hours
  3. C29 hours
  4. D24 hours
Show answer
Answer: (D) 24 hours Net filling per hour = 1/8 − 1/12 = 1/24, so 24 hours.
Question 16

A can complete a work in 12 days and B can complete it in 24 days. In how many days can they complete it working together?

  1. A10 days
  2. B8 days
  3. C7 days
  4. D18 days
Show answer
Answer: (B) 8 days Together they do 1/12 + 1/24 = 1/8 of the work per day, so 8 days.
Question 17

Pipe A can fill a tank in 12 hours and pipe B can empty it in 20 hours. If both are opened together, in how many hours will the empty tank be filled?

  1. A8 hours
  2. B35 hours
  3. C30 hours
  4. D27 hours
Show answer
Answer: (C) 30 hours Net filling per hour = 1/12 − 1/20 = 1/30, so 30 hours.
Question 18

A can complete a work in 12 days and B can complete it in 36 days. In how many days can they complete it working together?

  1. A9 days
  2. B13 days
  3. C8 days
  4. D11 days
Show answer
Answer: (A) 9 days Together they do 1/12 + 1/36 = 1/9 of the work per day, so 9 days.

These are RankerClub practice questions written in the UPSC Civil Services pattern. They are not official SSC/IBPS/RRB papers.

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