Question

Milk and cream are mixed together for a recipe. The total volume of the mixture is 1 cup. If the milk contains 2% fat, the cream contains 18% fat, and the mixture contains 6% fat, how much cream is in the mixture?

Answer 1

So this is a solution problem the answer is 3/4 cups or 75% milk and 1/4 cups or 25% cream, here's why:

m = milk

c = cream

m + c = 1

This is because when you add milk and cream then you get one cup of solution

.02m + .18c = .06

When you add together the percentages the goal is to have .06 or 6%

100m + 100c = 100

2m + 18c = 6

I do this to make it easier to solve

200m + 200c = 200

-200m - 1800c = -600

The "m's" cancel out

-1600c = -400

c = 1/4 or .25 or 25%

Now we add c back in

m + 1/4 = 1

Solve for m

m = 3/4

Thus: 3/4 milk and 1/4 cream