Selected MCQ

Current Question
If two pipes fill a tank in 6 hours, how long does one pipe take if the other fills in 10 hours?
  • A. 5 hours
  • B. 10 hours
  • C. 15 hours
  • D. 20 hours
Correct Answer: C
Explanation:
Using the rate formula gives 15 houRs.
Related Question 1
Three pipes of equal capacity fill a tank in 8 houRs. Two pipes will take ____.
  • A. 17 hours
  • B. 12 hours
  • C. 16 hours
  • D. 24 hours
Correct Answer: B
Explanation:
Work is inversely proportional.
Related Question 2
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 3
Pipes A, B, C fill tank in 12, 15, 20 houRs. If A alone works, time required is ____.
  • A. 6 hrs
  • B. 6⅔ hrs
  • C. 7 hrs
  • D. 7½ hrs
Correct Answer: C
Explanation:
Based on the given combination.
Related Question 4
Pipes A, B, C fill tank in 12, 15, 20 houRs. Find time together.
  • A. 6 hours
  • B. 6⅔ hours
  • C. 7 hours
  • D. 7½ hours
Correct Answer: C
Explanation:
Combined rate method.
Related Question 5
Three pipes fill a tank in 6 houRs. After 2 hours, one is closed. Remaining time is ____.
  • A. 10
  • B. 12
  • C. 14
  • D. 16
Correct Answer: C
Explanation:
Work-rate adjustment.