Question 343870
Let {{{A}}} be the amount of 10% nitric acid solution and let {{{B}}} be the amount of 40% nitric acid solution.
Total volume equation:
1.{{{A+B=12}}}
.
.
.
Concentration equation:
{{{10A+40B=20(12)}}}
{{{10A+40B=240}}}
2.{{{A+4B=24}}}
Subtract eq. 1 from eq. 2,
{{{A+4B-A-B=24-12}}}
{{{3B=12}}}
{{{highlight(B=4)}}}liters
Then from eq. 1,
{{{A+4=12}}}
{{{highlight(A=8)}}}liters