Question 908023
We have 32 oz of 4% milk fat
We want to add some 0% milk fat to make   2.5% milk fat
0*x+0.04*32=0.025(32+x)
0*x+1.28=0.8+0.025x
0x-0.025x=0.8-1.28
-0.025x=-0.48
x=19.2 oz at 0% (0.0) is added to 32 oz at 4%(1.28) to make 2.5% of 51.2 oz(1.28)
check
0*19.2+0.04*32=0.025(32+19.2)
0.0+1.28=0.025(51.2)
1.28=1.28
ok