Question 124264
You are close, but since the final solution is 500 ml and the first quantity is x ml, then the second quantity is {{{500-x}}} ml



So the equation should be


{{{0.75x+.25(500-x)=500(.55)}}}



{{{0.75x+.25(500-x)=275}}} Multiply



{{{0.75x+125-0.25x=275}}} Distribute



{{{0.50x+125=275}}} Combine like terms



{{{0.50x=150}}} Subtract 125 from both sides



{{{x=300}}} Divide both sides by 0.50 to isolate x




So you need 300 ml of the 75% solution