Question

10% of a water tank fills every 5 minutes. If you are filling a 40 gallon tank, how many gallons will there be in 30 minutes?

Answer 1

The volume after 30 minutes is:

`24~\text{gallons}`

Explanation:

Step 1: Knowing what 10% of the tank is

The volume of the tank is said to be
`40` gallons.

So,
`10\%` of that would be:

`10\%* 40\\\\=(10)/(100)* 40\\\\=4`

So,
`10\%` of the tank is equal to
`4` gallons.

Step 2: Knowing how full it will become

`10\%` of the tank is filled every 5 minutes.

Within 30 minutes, the cycle of 5 minutes is repeated:

`(30)/(5)\\\\=6~\text{times}`

When 5 minutes have passed 6 times, 30 minutes have passed in total.

This means that in that span of 30 minutes, the
`10\%` is filled six times.

This means that the volume increases by
`4~\text{gallons}` six times.

So, the final volume will be:

`(4* 6)\\\\=24\\\\=24~\text{gallons}`