# Lisa will make punch that is 25% fruit juice by adding pure fruit juice to a 2-liter mixture that is 10% pure fruit juice. How many liters of pure fruit juice does she need to add?

##### 3 Answers

Let's call the amount to be found

Then you will end up with

This will contain

The original 2 L allready contained

So we added

But this is also

I think

Have a look if it makes sense:

Suppose Lisa adds

The total amount of punch will be:

and the amount of pure juice in this is to be

The original punch contains

which when combined with

So,

which simplifies to

or