Question 868180
The final mixture will contain 0.06*249 = 14.94 gallons of butterfat
This will be made up of x gallons of 7% butterfat and 249-x gallons of 4% butterfat.
So we can write the following equation:
14.94 = 0.07x + 0.04(249-x)
Simplify and solve for x:
14.94 = 0.07x + 9.96 - 0.04x
This gives x = 166
Therefore, 166 gals of 7% and 83 gals of 4% should be used.