Question 206188
You have 90 gallons of a 15% antifreeze solution.
let x = the number of gallons of 50% antifreeze solution
{{{90*0.15 + 0.5x = 0.40(90+x)}}}
Solve for x.
{{{13.5 + 0.5x = 36+0.4x}}}
{{{0.1x = 22.5}}}
x = 225 gallons