Discussion of Question with ID = 039 under Pipes-and-Cisterns

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Question

Two pipes can together fill a cistern in 4 minutes. How long does the slower alone take if the speeds of the pipes are in the ratio 4 : 1?

A

20 mins.

B

21 mins.

C

19 mins.

D

22 mins.

Soln.
Ans: a

Let the time taken by the slower pipe alone be x. Then 4 × $(1/x + 4/x)$ = 1. Solving for x, we get x = 4 × 5 = 20 mins.


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