Selected MCQ

Current Question
If P works alone takes same time as Q and R together, time taken by P is ____.
  • A. 30 days
  • B. 25 days
  • C. 20 days
  • D. 15 days
Correct Answer: B
Explanation:
Based on the equality of work rates.
Related Question 1
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 2
If Q alone does work in 12 days and P is twice as fast, time together is ____.
  • A. 1
  • B. 2
  • C. 3
  • D. 4
Correct Answer: D
Explanation:
The combined rate gives 4 days.
Related Question 3
If P takes twice time of Q and thrice of R, total time taken is ____.
  • A. 7
  • B. 8
  • C. 9
  • D. 6
Correct Answer: D
Explanation:
Relative ratios simplify to 6.
Related Question 4
P completes work in 24 days, Q in 9 days, R in 12 days. Time taken together is ____.
  • A. 10
  • B. 9
  • C. 11
  • D. 12
Correct Answer: A
Explanation:
Sum of rates gives time = 10 days.
Related Question 5
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.