Question

The pump used to fill the water tank on a fire truck takes 40 minutes to fill the tank. If the pump sending water to the hose is on, it takes 60 minutes to fill the tank. If the pump filling the water tank is off, how long does the pump sending water to the hose take to empty the tank?
A) 120 minutes
B) 60 minutes
C) 30 minutes
D) 24 minutes

Answer 1

Answer:

A) 120 minutes

Step - by - step explanation:

The pump used to fill the water tank on a fire truck takes 40 minutes to fill the tank.

If the pump sending water to the hose is on, it takes 60 minutes to fill the tank.

Let's "x" be the amount of time to taken the pump sending water to the hose take to empty the tank.

1/40 - 1/x = 1/60

1/x = 1/40 - 1/60

1/x = (3 - 2)/120             Taking LCM as 120

1/x = 1/120

Cross multiplying, we get

120 = 1x

x  = 120/11

x = 120 minutes

Thank you.