A school pool fills up through one pipe in 4 hours, the other in 6 hours. How much will be left

A school pool fills up through one pipe in 4 hours, the other in 6 hours. How much will be left to fill after working together for an hour?

We will record the capacity of the school pool as 1.

In this case, through each pipe, in 1 hour of work, the following will be filled:

1/4 = 1/4 part of the pool (through 1 pipe).

1/6 = 1/6 of the pool (through 2 pipes).

We find which part of the pool will be filled through 2 pipes.

To do this, we summarize the resulting parts.

1/4 + 1/6 = 3/12 + 2/12 = 5/12 part.

From this it follows that it remains to fill in:

1 – 5/12 = 12/12 – 5/12 = 7/12 part of the pool.

Answer:

It will remain to fill 7/12 part of the pool after an hour of work.