Question

A chemist made 50 ounces of an acidic solution by mixing two different concentrations of the solution. He mixed x ounces of acidic solution with an 80% concentration and an acidic solution with 90% concentration. Which equation can be used to determine the concentration of the final solution?

Answer 1

What are your choices?

Answer 2

just add up the amounts of acid present. If there are x oz of 80% solution, then the rest (50-x) is 90%. That means that the final concentration c is found via

80x+90(50-x) = 50c
4500-10x = 50c

So, letting c(x) be the final concentration,

c(x) = 90-c/5

So, if x=0 (all 90% solution), c(0) = 90 and c(50) = 80 (all 80% solution).

Answer 3

oops: did you catch my typo?