# Pipes A and B are filling pipes while pipe C is an emptying pipe. A an

| Pipes A and B are filling pipes while pipe C is an emptying pipe. A and B can fill a tank in 72 and 90 minutes respectively. When all the three pipes are opened together, the tank gets filled in 2 hours. A and B are opened together for 12 minutes, then closed and C is opened. The tank will be empty after:

A. 12 minutes

B. 18 minutes

C. 16 minutes

D. 15 minutes

### Right Answer is: B

#### SOLUTION

Let the capacity of tank

Efficiency of B

Efficiency of

Tank filled by in 12 minutes

Time required by C to empty the tank

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Pipes A and B are filling pipes while pipe C is an emptying pipe. A an