How many liters of this solution should be drained and replaced w/ pure antifreeze to get a 52% solution?

Question

A car radiator contains 4 liters of 36% anti-freeze solution.

Answer 1

I won't do this for you -- but here is how you set it up.

Let X be the amount you drain.

Then (4-X) is the amount left in.

You then have X liters of 100%, (4-X) of 35% has to equal four liters at 52%. So:

1.00*X + 0.36*(4-X) = 0.52*(4)

Now -- you do the math.