Three pipes P, Q and R can fill a tank from empty to full in 40 minutes, 15 minutes, and 30 minutes respectively. When the tank is empty, all the three pipes are opened. P, Q and R discharge chemical solutions X, Y and Z respectively. What is the proportion of the solution Y in the liquid in the tank after 5 minutes? a) 8 / 15 b) 7 / 15 c) 8 / 17 d) 6 / 13 e) 8 / 13

1 Answer

Answer :

a

Part of the tank filled by pipe P in 1 minute = 1 / 40

Part of the tank filled by pipe Q in 1 minute = 1 / 15

Part of the tank filled by pipe R in 1 minute = 1/ 30

Here we have to find the proportion of the solution Y.

Pipe Q discharges chemical solution Y.

Part of the tank filled by pipe Q in 5 minutes

= 5 × 1 / 15 = 1 / 3

Part of the tank filled by pipe P, Q, R together in 1 minute

= 1/40 + 1/15 + 1/30

= (3+8+4)/120 = 15 / 120 = 1 / 8.

Part of the tank filled by pipe P, Q, R together in 5 minute

= 5 × 1/8 = 5/ 8

Required proportion = (1/3) / ( 5/8) = 8 / 15

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