# How many quarts of milk containing 4% butter fat and how many quarts of cream containing 29% butter fat must be mixed to make 40 quarts of cream containing 20% butter fat?

##### 1 Answer

Aug 18, 2015

Derive two linear equations from the description and solve by substitution to find that

#### Explanation:

Suppose we combine

We want:

From the first of these we get

Substitute this into the second equation to get:

Add

Multiply both sides by

Then

Check: