Answer:
50
Step-by-step explanation:
The amount of 4% butterfat milk is equal to x quarts , When 1% butterfat milk is equal to 75-x. The amount of butterfat in 4% butterfat milk is x/100*4=0.04x
The amount of butterflat in 1% butterfat milk is (75-x)/100= 0,75-0.01x
1The amount of butterflat in 75 quarts of 3% butterfat milk (our desired mixture) is 75/100*3= 2.25
This quantity (2.25) is the sum of butterfat from 4% butterfat milk and 1% butterfat milk(the sum of 0.04x and 0.75-0.01x)
the equation is
0.04x+0.75-0.01x=2.25
0.03x=1.5
x=50