Question

An aquarium tank can hold 5400 liters of water. There are two pipes that can be used to fill the tank. The first pipe alone can fill the tank in 45 minutes. The second pipe can fill the tank in 36 minutes by itself. When both pipes are working together, how long does it take them to fill the tank?

Answer 1

Answer:

20 min

Step-by-step explanation:

Rate of pipe1   = 1 tank / 45 min

rate of pipe2   = 1 tank / 36 min

Now find the time required when both rates are used

1 tank / ( 1 tank/45 min  + 1 tank/ 36 min) = 20 min