Question

A chemist is mixing a solution that is 2% acid and another solution that is 8% acid. She needs to make 75

ml of a solution that is 5% acid. How much of each solution should she use?

Answer 1

37.5 ml of 2% solution and

37.5 ml of 8% solution

Explanation:

x = 2% solution

y = 8% solution

system of equations:

x + y = 75

.02x + .08y = 75(.05)

substitution method:

let y = 75 - x

.02x + .08(75 - x) = 3.75

.02x + 6 - .08x = 3.75

6 - .06x = 3.75

-.06x = -2.25

x = 37.5

y = 75 - 37.5

y = 37.5