Question 1096956
Let {{{X}}} be the amount of 4% solution.
Let {{{Y}}} be the amount of 15% solution.
1.{{{X+Y=44}}} Total volume.
.
.
2.{{{4X+15Y=12(X+Y)=12(44)=528}}} Total concentration.
Multiply eq.1 by 4 and subtract from eq. 2,
{{{4X+15Y-4X-4Y=528-176}}}
{{{11Y=352}}}
Solve for Y then use either equation to solve for X.