Question 387048
Let A be the amount of 5% solution and B the amount of 10% solution.
1.{{{A+B=5}}}
.
.
{{{5A+10B=7(5)}}}
2.{{{A+2B=7}}}
Subtract eq. 1 from eq. 2,
{{{A+2B-A-B=7-5}}}
{{{highlight(B=2)}}}liters
.
.
Then from eq. 1,
{{{A+2=5}}}
{{{highlight(A=3)}}}liters