Pipes and Cisterns Practice Test 2 with solutions

Question : 12 of 40

Marks: +1, -0

Two pipes A and B together can fill a cistern in 4 hours. Had they been opened separately, then B would have taken 6 hours more than A to fill the cistern. How much time will be taken by A to fill the cistern separately?

8 hrs.
6 hrs.
2 hrs.
1 hr.

Validate

Solution:

Let x and (x + 6) hours be the time taken by pipes A and B respectively to fill the cistern, then

1/x+1/{x+6}

1/4

⇒

{2x+6}/{x^2+6x}

1/4

⇒ (x – 6) (x + 4) = 0
∴ x = 6
(Taking positive value)
Hence, time taken by A alone to fill the cistern is 6 hours.

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