<PRE><B>Question 287930</B>
You have 2 drums of milk, one contains 16% butterfat, the other contains 48% butterfat.
 You need 40 gallons of milk at 30% butterfat.
 How many gallons of each do you have to mix?
:
Let x = amt of 48% milk
the result is to be 40 gal, therefore:
(40-x) = amt of 16% milk
:
At typical mixture equation using decimal equiv of percent:
.48x + .16(40-x) = .30(40)
:
.48x + 6.4 - .16x = 12
:
.48x - .16x = 12 - 6.4
:
.32x = 5.6
x = {{{5.6/.32}}}
x = 17.5 gal of 48% milk
and
40 - 17.5 = 22.5 gal of 16% milk
;
:
Check solution in original equation
.48(17.5) + .16(22.5) = .30(40)
8.4 + 3.6 = 12; confirms our solutions</PRE>