How many gallons of milk that is 10 percent butter-fat must be added to 8 gallons of milk that is 50 percent butterfat to obtain milk that is 20 percent butterfat?  Pick one:
A) 6
B) 12
C) 14
D) 24
E) 28

Rationale: "equate the fat : 0.1 x + 0.5 * 8 = 0.2 ( x + 8 ) - - > x = 24 . answer : d ."
Answer: D