Question

two pipes x and y can fill a tank in 20 minutes and 30 minutes respectively. if both the pipes are opened together, after how many minutes will the tank get filled?

Answer 1

Pipe X can fill the tank in = 20 minutes

In 1 minute, X will fill = 1/20

Pipe Y can fill the tank in = 30 minutes

In 1 minute, Y will fill = 1/30

In 1 minute, both will fill = 1/20 + 1/30 = (3+2)/60 = 5/60 = 1/12

To fill completely, time required= 1 ÷ 1/12 = 12 minutes

Thus, if both the pipes are opened together, they will take 12 minutes to fill the tank