Question 963159
1.{{{2X+5Y=(5/2)(250)}}}
2.{{{X+Y=250}}}
Multiply eq. 2 by -2 and add to eq. 1,
{{{2X+5Y-2X-2Y=625-500}}}
{{{3Y=125}}}
{{{Y=125/3}}}<--- gallons of 5% solution
Then,
{{{X+125/3=750/3}}}
{{{X=625/3}}}<--- gallons of 2% solution