The tank will be filled through the first pipe in 36 minutes, how many minutes will the tank be filled

The tank will be filled through the first pipe in 36 minutes, how many minutes will the tank be filled through the second pipe, if the two pipes together fill it in 20 minutes?

Let’s designate the volume of the tank as 1.

In this case, if it is filled only with the first pipe, then in 1 minute it will be filled by:

1/36 = 1/36 part.

In the event that it is filled through 2 pipes, then in 1 minute it will be filled by:

1/20 = 1/20 part.

We will find to what part the tank will be filled through the second pipe in a minute.

1/20 – 1/36 = (common denominator 180) = 9/180 – 5/180 = 4/180 = 1/45.

This means that through the second pipe, the tank will be filled in:

1 / 1/45 = 1 * 45/1 = 45 minutes.

Answer:

After 45 min.