Wayne has milk that is 15% butterfat and skim milk without butterfat. How much 15% butterfat milk and how much skim milk should he mix to make 200 gallons of milk that is 13.5% butterfat?

Answer and Step by Step Explanation

Let +x+ = gallons of skim milk needed

+.05%2A80+=+4+ gallons of butterfat in 5% milk

+4+%2F+%28+80+%2B+x%29+=+.02+

+4+=+.02%2A%28+80+%2B+x+%29+

+4+=+1.6+%2B+.02x+

+.02x+=+4+-+1.6+

+.02x+=+2.4+

+x+=+120+

120 gallons of skim milk must be added

check:

+4+%2F+%28+80+%2B+x%29+=+.02+

+4+%2F+%28+80+%2B+120%29+=+.02+

+4+%2F+200+=+.02+

+4+=+4+

you have 6 cupcakes

correct answer:

b.(19,-2)