Question

A scientists has a container of %2 acid solution and a container of 5% acid solution. How many fluid ounces of each concentration should be combined to make 25fl oz of 3.2% acid solution?

Answer 1

Answer: 15 oz of 2% solution and 10 oz of 5% solution

Step-by-step explanation:

Set up a table with the given information. Multiply across and add down. The bottom row (Total) will provide the equation. Then, solve the equation for the variable (2% solution) and substitute that value into the quantity for the 5% solution to find that value.

$\begin {array}{l|c|c||l}&Quantity&Percent&Qty\times Percent\\ Solution\ A&x&2\%=0.02&\qquad 0.02(x)=0.02x\\Solution\ B&25-x&5\%=0.05&0.05(25-x)=1.25-0.05x\\Total&25&3.2\%=0.032&0.02x+1.25-0.05x\\\end{array} \\\\\\.\qquad 25(0.32) = 1.25-0.03x\\.\qquad \qquad -0.8 = 1.25 - 0.03x\\.\qquad \quad \ -0.45 = -.03x\\.\qquad \qquad \ 15 = x\\\\Solution\ A: x = 15\\Solution\ B: 25 - x = 25 - (15) = 10$