Question

A scientist has two solution which she has labeled solution A and solution B. Each contain salt. she knows that solution A is 70% salt and solution B is 95% salt. she want to obtain 170 ounces of a mixture that is 80% salt. how many ounces of each solution should she use

Answer 1

start by making a balance from the solution fro the ounces and for the salt

$\begin{gathered} A+B=170 \\ 0.7A+0.95B=136 \end{gathered}$

Clear one of the variables from the first equations

$B=170-A$

Replace B in the second equation

$\begin{gathered} 0.7A+0.95(170-A)=136 \\ 0.7A+161.5-0.95A=136 \\ -0.25A=-25.5 \\ A=102 \end{gathered}$

use the value of A to find B

$\begin{gathered} B=170-102 \\ B=68 \end{gathered}$