How much low fat milk(1%) and whole milk(4%) should be mixed to make 5 gallons of reduced fat milk (2%)?

Answer 1

a =1%
5 -a = 4%

0.01a+ 0.04(5-a) = 5(0.02)

.0.01a+ 0.2 -0.04a = 0.1

-0.03a + .2 = 0.1

-0.03a + .2 -.2 = 0.1-0.2

-.03a = -.1

a = 10/3
4% = 5-a
5/3
10/3 mixed with low fat milk (1%)
5/3 mixed with whole milk(4%)