Two solutions of different concentrations of acid are mixed creating 40 ml of a solution that is 32% acid. one-quarter of the solution is made up of a 20% acid solution. the remaining three-quarters is made up of a solution of unknown concentration, c.
which equation can be used to determine c, the unknown concentration?
30c + 10(0.2) = 40(0.32)
startfraction 3 over 4 endfraction left-parenthesis c right parenthesis plus startfraction 1 over 4 endfraction left-parenthesis 0.2 right-parenthesis equals 40 times 0.32.(c) + startfraction 1 over 4 endfraction cup.(0.2) = 40(0.32)
(c)( (0.2)) = 40(0.32)
30(c)(10(0.2)) = 40(0.32)

If is the unknown concentration of the second solution, then each mL of this solution that is used in the new one contributes mL of acid.

There are 40 mL of the new solution, and one quarter is made up of 20% acid while the remaining three-quarters is made up of the solution - that is, 10 mL of a 20% acid solution are used, so that its contribution is 0.2(10 mL) = 2 mL of acid, while 30 mL of the solution are used, so it contributes of acid.

In this new solution, we want to get a concentration of 32% acid, so it should contain 0.32(40 mL) = 12.8 mL of acid. Then the total amount of acid in the new solution satisfies

so the second solution has a concentration of 36%. The equation used here is the same as the first choice (a),

m a t h w a y. c o m

step-by-step explanation: