ANSWER:
264 gallons of milk containing 8% butterfat
132 gallons of milk containing 2% butterfat
Explanation:
From the statement we can propose the following system of equations:
Let x be the milk that contains 8% butterfat and let y be the 2%.
We substitute in equation (1) in equation (2) and substitute for x, just like this:
Knowing the value of x, we can calculate the value of y, substituting in equation 1, like this:
Therefore, 264 gallons of milk containing 8% butterfat and 132 gallons of milk containing 2% butterfat are needed.