Problema Solution

A dairy operator has some milk of 2.5% butterfat, and some milk of 4% butterfat. How many gallons of each kind must she mix to get 100 gallons of milk of 3% butterfat?

Answer provided by our tutors

First we must create variables, lets say A = gallons of 2.5% butter milk and B = gallons of 4% buttermilk.  

So one milk has 2.5% butter fat while the other has 4% butter fat, and together they must = 100 gallons. So, lets make our first equation which is 

A+B = 100

Then another equation will be combingin the percentages.

.025A + .04B = (.03) 100

when we slove for A we get A = 100 - B

The we plug this into the other equation .025(100 - B) + .04B = 2.5 + .015B = 3

solve for B and we get B = 100/3

we plug B into the equation A+B=100 and get A=200/3

therefore, we need 200/3 gallons of 2.5% milk and 100/3 gallons of 4% milk.