Question

Hey, can you help me out here (please)?

Answer 1

In the x quarts of 2% fat milk, there is 0.02x quarts of fat.
in the y quarts of 4% fat milk there is 0.04y quarts of fat.
together, there is (x+y) quarts of milk, and 0.24 quarts of fat.
the equations are:
x+y=9
0.02x+0.04y=0.24
multiply the first equation with 0.02: 0.02x+0.02y=0.18
subtract this new equation from equaition 2 to eliminate x:
0.04y-0.02y=0.24-0.18
0.02y=0.06
y=3
x=9-3=6
x is twice as much as y.
He used twice as much as the 2% fat milk than the 4% fat milk. 
so the first choice is the correct answer.