Question

Two pipes A and B can fill a tank in 15 and 30 minutes respectively. If both the pipes are used together, then how long will it take to fill the tank?

• A. 5 minutes
• B. 10 minutes
• C. 15 minutes
• D. 20 minutes

Answer 1

The correct option is B 10 minutes

Let the volume of the tank be v litres:

Tank filled by (A + B) in 1 min $=$ $\frac{v}{15}+\frac{v}{30}$

$=\frac{45v}{450}$

$=\frac{v}{10}$

Therefore, both pipes can fill the tank of v litres in 10 minutes.