Question 73672
5*.10+x*.40=(5+x).20
.5+.4x=1+.2x
.4x-.2x=1-.5
.2x=.5
x=.5/.2
x=2.5 gallons of 40% gluocose is required to make the 20% mixture.
proof
5*.10+2.5*.4=(5+2.5).2
.5+1=7.5*.2
1.5=1.5