3 Pipes : 2 In and 1 Out

Pipes A and B fill a tank in 30 minutes and 15 minutes. Pipe C drains 12 liters of water in a minute. If all of them are kept open when the tank is full, the tank empties in 30 minutes. How much water the tank can hold?

Trick/ Formula: Full tank + Input = Output

Let X be the capacity of the tank.

X + Input in 30 minutes = Output in 30 minutes

X +   30 *( x/30 + x/15) = 30*12

4x=360;   x = 90 ltr


In 1 minute, pipe A can fill 1/30th & B can fill 1/15th of the tank’s capacity.

Capacity of pipe A = 1/30

Capacity of B = 1/15



Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s