A dairy needs 372 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 372 gallons?

Question

A dairy needs 372372 gallons of milk containing 6%6% butterfat. How many gallons each of milk containing 7%7% butterfat and milk containing 3%3% butterfat must be used to obtain the desired 372372 gallons?

Answer 1

7-6=1

6-3=3

3 times as much 3% as 7% is needed

372/4= 93 gallons 7%

mixed with

3x93= 279 gallons 3%

yield

372 gallons 6%

.07x +.03(372-x)=.06(372

.04x =.03(372)

x= .03(372)/.04

x= 3(93)=279 gal 7%

372-279= 93 gal 3%