Pipes and Cistern: Essential Concepts for Competitive Exams

Pipes and Cistern

Q. Two pipes can fill a tank in 6 hours and 9 hours respectively. How long will it take to fill the tank if both pipes are opened together?

Solution

The combined rate is 1/6 + 1/9 = 3/18 + 2/18 = 5/18. Therefore, it will take 18/5 hours or 3.6 hours.

Correct Answer: B — 3 hours

Q. Two pipes can fill a tank in 8 hours and 12 hours respectively. If both pipes are opened together, how long will it take to fill the tank?

Solution

The combined rate is 1/8 + 1/12 = 5/24. Therefore, time taken = 24/5 = 4.8 hours.

Correct Answer: A — 4.8 hours

Q. Two pipes can fill a tank in 9 hours and 12 hours respectively. If both pipes are opened together, how long will it take to fill the tank?

Solution

The combined rate is 1/9 + 1/12 = 7/36. Therefore, it will take 36/7 = 5.14 hours to fill the tank.

Correct Answer: C — 6 hours

Showing 61 to 63 of 63 (3 Pages)