Amount x Rate (%) = Quantity

Question

A dairy needs 232 gallons of milk containing 6% butterfat. How many gallons each of milk containing 7% butterfat and milk containing 3% butterfat must be used to obtain the desired 232 gallons?

Answer 1

Let x = number of gallons of 3% milk

    232 - x = number of gallons of 7% milk

 

0.03x + 0.07(232 - x) = 0.06(232)

 

0.03x + 16.24 - 0.07x = 13.92

 

-0.04x = -2.32

 

x = 58 gallons

 

We need 58 gallons of 3% butterfat milk and 174 gallons of 7% butterfat milk to obtain 232 gallons of 6% butterfat milk.