Question 347647
Let A be the amount of 10% solution.
Let B be the amount of 2%solution.
.
.
Volume equation:
1.{{{A+B=200}}}
Concentration equation:
{{{10A+2B=8(200)=1600}}}
2.{{{5A+B=800}}} 
Subtract eq. 1 from eq. 2,
{{{5A+B-A-B=800-200}}}
{{{4A=600}}}
{{{highlight(A=150)}}}ml
Then from eq. 1,
{{{150+B=200}}}
{{{highlight(B=50)}}}ml