Question 1092268
x, how much of 90% antifreeze


{{{(90x+15*100)/(x+100)=80}}}

-

{{{90x+1500=80(x+100)}}}

{{{9x+150=8(x+100)}}}

{{{9x+150=8x+800}}}

{{{x=800-150}}}

{{{highlight_green(x=650)}}}, gallons of the 90% antifreeze