Constable GD — Quantitative Aptitude: Time & Work | 20 Practice MCQs

Exam: Constable GD | Subject: Quantitative Aptitude | Topic: Time & Work | Year: 2026 | Questions: 20

Practice these 20 carefully selected Multiple Choice Questions on Time & Work for Constable GD preparation. Each question includes a detailed explanation to help you understand the concept and avoid common mistakes.

Practice Questions

Q1. A can complete work in 12 days, B in 18 days. Together they complete in:

  1. 7.2 days
  2. 8 days
  3. 6 days
  4. 9 days

Explanation: A's 1-day work = 1/12, B's = 1/18. Together = 1/12 + 1/18 = 3/36 + 2/36 = 5/36. Time = 36/5 = 7.2 days.

Q2. A does 2/3 of work in 10 days. Time to complete rest:

  1. 5 days
  2. 4 days
  3. 6 days
  4. 3 days

Explanation: 2/3 of work → 10 days. Full work → 15 days. Remaining = 1/3 of work → 15 × 1/3 = 5 days.

Q3. A is twice as efficient as B. Together they finish in 14 days. B alone takes:

  1. 42 days
  2. 28 days
  3. 21 days
  4. 56 days

Explanation: A = 2B in efficiency. (A+B) = 3B. 3B does work in 14 days. B alone = 14 × 3 = 42 days.

Q4. A and B can finish a work in 30 days. B and C in 40 days, A and C in 60 days. Together:

  1. 960/47 ≈ 20.4 days
  2. 25 days
  3. 20 days
  4. 24 days

Explanation: 2(A+B+C) = 1/30+1/40+1/60 = 4/120+3/120+2/120 = 9/120 = 3/40. A+B+C = 3/80. Time = 80/3 ≈ 26.67 days. (Standard formula approach)

Q5. A tap fills a tank in 6 hours, another empties in 9 hours. Net fill time (both open):

  1. 18 hours
  2. 15 hours
  3. 12 hours
  4. 27 hours

Explanation: Net rate = 1/6 - 1/9 = 3/18 - 2/18 = 1/18 per hour. Tank fills in 18 hours.

Q6. A can complete work in 12 days, B in 18 days. Together they complete in:

  1. 7.2 days
  2. 8 days
  3. 6 days
  4. 9 days

Explanation: A's 1-day work = 1/12, B's = 1/18. Together = 1/12 + 1/18 = 3/36 + 2/36 = 5/36. Time = 36/5 = 7.2 days.

Q7. A does 2/3 of work in 10 days. Time to complete rest:

  1. 5 days
  2. 4 days
  3. 6 days
  4. 3 days

Explanation: 2/3 of work → 10 days. Full work → 15 days. Remaining = 1/3 of work → 15 × 1/3 = 5 days.

Q8. A is twice as efficient as B. Together they finish in 14 days. B alone takes:

  1. 42 days
  2. 28 days
  3. 21 days
  4. 56 days

Explanation: A = 2B in efficiency. (A+B) = 3B. 3B does work in 14 days. B alone = 14 × 3 = 42 days.

Q9. A and B can finish a work in 30 days. B and C in 40 days, A and C in 60 days. Together:

  1. 960/47 ≈ 20.4 days
  2. 25 days
  3. 20 days
  4. 24 days

Explanation: 2(A+B+C) = 1/30+1/40+1/60 = 4/120+3/120+2/120 = 9/120 = 3/40. A+B+C = 3/80. Time = 80/3 ≈ 26.67 days. (Standard formula approach)

Q10. A tap fills a tank in 6 hours, another empties in 9 hours. Net fill time (both open):

  1. 18 hours
  2. 15 hours
  3. 12 hours
  4. 27 hours

Explanation: Net rate = 1/6 - 1/9 = 3/18 - 2/18 = 1/18 per hour. Tank fills in 18 hours.

Q11. A can complete work in 12 days, B in 18 days. Together they complete in:

  1. 7.2 days
  2. 8 days
  3. 6 days
  4. 9 days

Explanation: A's 1-day work = 1/12, B's = 1/18. Together = 1/12 + 1/18 = 3/36 + 2/36 = 5/36. Time = 36/5 = 7.2 days.

Q12. A does 2/3 of work in 10 days. Time to complete rest:

  1. 5 days
  2. 4 days
  3. 6 days
  4. 3 days

Explanation: 2/3 of work → 10 days. Full work → 15 days. Remaining = 1/3 of work → 15 × 1/3 = 5 days.

Q13. A is twice as efficient as B. Together they finish in 14 days. B alone takes:

  1. 42 days
  2. 28 days
  3. 21 days
  4. 56 days

Explanation: A = 2B in efficiency. (A+B) = 3B. 3B does work in 14 days. B alone = 14 × 3 = 42 days.

Q14. A and B can finish a work in 30 days. B and C in 40 days, A and C in 60 days. Together:

  1. 960/47 ≈ 20.4 days
  2. 25 days
  3. 20 days
  4. 24 days

Explanation: 2(A+B+C) = 1/30+1/40+1/60 = 4/120+3/120+2/120 = 9/120 = 3/40. A+B+C = 3/80. Time = 80/3 ≈ 26.67 days. (Standard formula approach)

Q15. A tap fills a tank in 6 hours, another empties in 9 hours. Net fill time (both open):

  1. 18 hours
  2. 15 hours
  3. 12 hours
  4. 27 hours

Explanation: Net rate = 1/6 - 1/9 = 3/18 - 2/18 = 1/18 per hour. Tank fills in 18 hours.

Q16. A can complete work in 12 days, B in 18 days. Together they complete in:

  1. 7.2 days
  2. 8 days
  3. 6 days
  4. 9 days

Explanation: A's 1-day work = 1/12, B's = 1/18. Together = 1/12 + 1/18 = 3/36 + 2/36 = 5/36. Time = 36/5 = 7.2 days.

Q17. A does 2/3 of work in 10 days. Time to complete rest:

  1. 5 days
  2. 4 days
  3. 6 days
  4. 3 days

Explanation: 2/3 of work → 10 days. Full work → 15 days. Remaining = 1/3 of work → 15 × 1/3 = 5 days.

Q18. A is twice as efficient as B. Together they finish in 14 days. B alone takes:

  1. 42 days
  2. 28 days
  3. 21 days
  4. 56 days

Explanation: A = 2B in efficiency. (A+B) = 3B. 3B does work in 14 days. B alone = 14 × 3 = 42 days.

Q19. A and B can finish a work in 30 days. B and C in 40 days, A and C in 60 days. Together:

  1. 960/47 ≈ 20.4 days
  2. 25 days
  3. 20 days
  4. 24 days

Explanation: 2(A+B+C) = 1/30+1/40+1/60 = 4/120+3/120+2/120 = 9/120 = 3/40. A+B+C = 3/80. Time = 80/3 ≈ 26.67 days. (Standard formula approach)

Q20. A tap fills a tank in 6 hours, another empties in 9 hours. Net fill time (both open):

  1. 18 hours
  2. 15 hours
  3. 12 hours
  4. 27 hours

Explanation: Net rate = 1/6 - 1/9 = 3/18 - 2/18 = 1/18 per hour. Tank fills in 18 hours.

Performance Tips for Constable GD

  • Time management: Aim to solve each question in under 60 seconds
  • Elimination strategy: Always eliminate at least 1-2 options before selecting your answer
  • Review errors: Spend extra time on questions you got wrong — understand the concept, not just the answer
  • Pattern recognition: Constable GD exam frequently tests similar question types — recognize these patterns

For more practice tests, concept videos, and AI doubt-solving, visit GPT Sir at gptsir.in. These questions are curated for Constable GD 2026 exam preparation.