Question 704695
Question #2, the acid mixture:

x and y, the volume of low and high concentration acids
Solve this system:
{{{x+y=50}}}
{{{(x*0.06+y*0.10)/50=0.0728}}}


The rational one rearranges to 6x+10y=50*7.28, then 6x+10y=364, then 3x+5y=182
So an easier but equivalent system to solve is
{{{x+y=50}}}
{{{3x+5y=182}}}


You might continue by taking the x+y=50 and multiply both sides by 3, and subtracting the equation from the "182" equation, and find a value for y.  

3x+5y=182
-(3x+3y)=-(150)
________________
0+2y=32
y=16.
{{{highlight(y=16)}}} cubic centimeter for the 10% acid, so....