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