Answer : The volume of solution used should be, 12 L
Explanation :
Let the volume of solution be, x
Thus the equation will be:
[tex]25\%\times (x)+40\%\times (18-x)=30\%\times (18)[/tex]
Now solving the term 'x', we get:
[tex]\frac{25}{100}\times (x)+\frac{40}{100}\times (18-x)=\frac{30}{100}\times (18)[/tex]
[tex]0.25\times (x)+0.4\times (18-x)=0.3\times (18)[/tex]
[tex]0.25x+7.2-0.4x=5.4[/tex]
[tex]-0.15x=-1.8[/tex]
[tex]0.15x=1.8[/tex]
[tex]x=12[/tex]
Thus, the volume of solution used should be, 12 L
