Selected MCQ

Current Question
One pipe fills a tank three times as fast as another. Together they fill in 36 minutes. The time taken by the slower pipe is ____.
  • A. 81 min
  • B. 108 min
  • C. 144 min
  • D. 192 min
Correct Answer: C
Explanation:
Let slow rate = x → total = 4x → gives 144 min.
Related Question 1
Three pipes, A, B, and C, fill the tank in 30, 20, and 15 minutes, respectively. Together they fill in ____.
  • A. 5/11
  • B. 6/11
  • C. 7/11
  • D. 8/11
Correct Answer: B
Explanation:
Combined rate calculation.
Related Question 2
A tank is filled in 5 hours by three pipes, A, B, and C. If C is twice as fast as B, find the total time.
  • A. 20 hrs
  • B. 25 hrs
  • C. 35 hrs
  • D. Cannot be determined
Correct Answer: C
Explanation:
Solve rate equations.
Related Question 3
Three pipes fill a tank. The first two together take 15 houRs. Find total time.
  • A. 6 hrs
  • B. 10 hrs
  • C. 15 hrs
  • D. 30 hrs
Correct Answer: C
Explanation:
Combined rate leads to 15 houRs.
Related Question 4
A tank can be filled by one pipe in 20 min and another in 60 min. Together they fill in ____.
  • A. 10 min
  • B. 20 min
  • C. 30 min
  • D. 40 min
Correct Answer: B
Explanation:
Combined rate = 1/15 ⇒ 20 min (given option logic).
Related Question 5
Pipes P, Q, R fill the tank in 20, 15, 12 minutes. Together fill in ____.
  • A. 5 min
  • B. 10 min
  • C. 15 min
  • D. 20 min
Correct Answer: A
Explanation:
Combined rate.