Question 70275
1X+.4(55-X)=.75*55
X+22-.4X=41.25
.6X=41.25-22
.6X=19.25
X=19.25/.6
X=32.0833 GALLONS  OF 100% SOLUTION IS NEEDED.
PROOF
32.0833+.4(55-32.08333)=41.25
32.08333+22-12.8333=41.25
54.08333-12.8333=41.25
41.25=41.25