Question 363211
Let A be the amount of 13% solution, B the amount of 18% solution.
1.{{{A+B=50}}}
.
.
{{{13A+18B=17(50)}}}
2.{{{13A+18B=850}}}
Multiply eq. 1 by (-13) and add to eq. 2,
{{{-13A-13B+13A+18B=-650+850}}}
{{{5B=200}}}
{{{highlight(B=40)}}}ml
Then from eq. 1,
{{{A+40=50}}}
{{{highlight(A=10)}}}ml