Question

if holstein cows produce milk that is on average 3.66% butterfat and jersey cows produce milk that is on average 4.5% butterfat, how many gallons of jersey milk should be added to every 100 gal of holstein milk to have milk that is 4% butterfat?

Answer 1

Answer: 68 gallons.

Explanation:

let x represent the gallons needed to be added to holstein milk

(100 x 3.66%) + (x x 4.5%) / (100 + x) = 4%

(100 x 0.0366)+(x x 0.045) / (100 + x) = 0.04

(3.66+0.045x) / (100 + x) = 0.04

3.66+0.045x = 0.04(100+x)

3.66+0.045x = 4+0.04x (subtract 0.04x both sides)

0.005x=0.34

(divide both sides by 0.005)

x=0.34/0.005

x=68 gallons