# My fuel is at 80% full. After traveling some distance, only 30% of that fuel is left. I fill the tank to full capacity by putting in 19 gallons. What is the full capacity of my tank?

##### 2 Answers

25 gallons

#### Explanation:

First you have to find what percent of the tank is left after 30% of 80% of the fuel has been spent

multiply

now subtract

```
76% of the tank equals 19 gallons
set up a ratio
```

Now divide both sides by 76

Full tank capacity is 25 gallons

#### Explanation:

The only thing we are interested is the tank. Not the distance travelled.

The tank has 30% of its original content left.

Thus the amount of fuel left is 30% of 80%

Amount of the whole tank taken up by fuel is:

So the free space left in the tank by volume is

We know that it takes 19 gallons to fill up the 76% volume left.

So by ratio we have:

To change 76 into 100 we multiply it by