Question 1055407
James wishes to obtain 800 mL of a 7% solution of boric acid by mixing 4% and 12% solutions. How much of each should be used?
<pre>Let amount of 4% solution to mix, be F
Then amount of 12% solution to mix is: 800 - F
The following equation is thus formed: .04F + .12(800 - F) = .07(800)
.04F + 96 - .12F = 56
.04F - .12F = 56 - 96
- .08F = - 40
{{{highlight_green(matrix(1,13, F, or, amount, of, "4%", solution, to, mix, "=", (- 40)/(- .08), or, 500, mL))}}}
{{{highlight_green(matrix(1,11, Amount, of, "12%", solution, to, mix, "=", 800 - 500, or, 300, mL))}}}