Problema Solution

An aquarium tank can hold 6000 liters of water. There are two pipes that can be used to fill the tank. The first pipe alone can fill the tank in 40 minutes. The second pipe can fill the tank in 60 minutes by itself. When both pipes are working together, how long does it take them to fill the tank?

Answer provided by our tutors

let 'x' be the time (in hours) the both pipes need to fill the tank together


the first pipe alone fills the tank in 40 min = 40/60 hours = 2/3 hours

the second pipe alone fills the tank in 60 min = 60/60 hours = 1 hour


if they work together in 1 hour they will fill


1/(2/3) + 1/1 = 1/x


3/2 + 1 = 1/x


1/x = 5/2


x = 2/5 = 0.4 hours = 0.4*60 min = 24 min


both pipes will fill the tank is 24 minutes.


let 'x' be the time (in hours) the both pipes need to fill the tank together


the first pipe alone fills the tank in 40 min = 40/60 hours = 2/3 hours

the second pipe alone fills the tank in 60 min = 60/60 hours = 1 hour


if they work together in 1 hour they will fill


1/(2/3) + 1/1 = 1/x


3/2 + 1 = 1/x


1/x = 5/2


x = 2/5 = 0.4 hours = 0.4*60 min = 24 min


both pipes will fill the tank in 24 minutes.