Question 340459
Let A be the amount of 2% solution, B the amount of 10% solution.
1.{{{A+B=500}}}
.
.
.
{{{2A+10B=5(500)}}}
{{{2A+10B=2500}}}
2.{{{A+5B=1250}}}
Subtract eq. 1 from eq. 2,
{{{A+5B-A-B=1250-500}}}
{{{4B=750}}}
{{{highlight(B=375/2)}}}ml
Then from eq. 1,
{{{A+375/2=1000/2}}}
{{{highlight(A=625/2)}}}ml