Question

you have an unlimited supply of 5% saline solution and 8% saline solution. How much of each type would you have to use to create 60 ounces of 7% saline solution? Write and solve a system of equations to model and solve this problem.

Answer 1

amount of 5% solution used --- x
amount of 8% solution used --- 60-x

.05x + .08(60-x) = .07(60)
times 100
5x +8(60-x) = 420
5x + 480 - 8x = 420
-3x = -60
x = 20

20 ounces of the 5% solution and 40 ounces of the 8% solution.