Answer:
First Solution: 8.5mL
Second Solution: 42.5 mL
Explanation:
Let us call x the number of mL of the first solution and y the number of mL of the second solution.
Now, from the fact that the final solution is 51 mL, we know that
[tex]x+y=51[/tex]Furthermore, from the fact that the final solution 40% carbonated water, meaning there are in total
[tex]51\times\frac{40}{100}=20.4mL[/tex]of carbonated water in the love potion.
Now, the first solution contributes 15/100 * x mL of carbonated water in the solution whereas the second solution contributes 45/100 * y mL. Since all 20.4 mL of carbonated water in the solution is coming from solution 1 and 2, then it must be that
[tex]\frac{15}{100}x+\frac{45}{100}y=20.4[/tex][tex]0.15x+0.45y=20.4[/tex]Thus we have two equations and two unknowns
[tex]\begin{gathered} 0.15x+0.45y=20.4 \\ x+y=51 \end{gathered}[/tex]We solve the above system by elimination.
First multiplying the second equation by 0.15 gives
[tex]\begin{gathered} 0.15x+0.45y=20.4 \\ 0.15x+0.15y=51\cdot0.15 \end{gathered}[/tex]which simplifies to give
[tex]\begin{gathered} 0.15x+0.45y=20.4 \\ 0.15x+0.15y=7.65 \end{gathered}[/tex]Subtracting the first equation from the second gives
[tex]0.30y=12.75[/tex]Finally, dividing both sides by 0.30 gives
[tex]\boxed{y=42.5.}[/tex]With the value of y in hand, we now put it into x+ y = 51 and solve to x to get
[tex]x+42.5=51[/tex]subtracting 42.5 from both sides gives
[tex]\boxed{x=8.5.}[/tex]Hence, to conclude the needed amounts of the solution are:
First Solution: 8.5mL
Second Solution: 42.5 mL