how many liters of a 10% acid solution must be mixed with three liters of a 4% acid solution to get an 8% acid

Question

solution? Please show your work.

Answer 1

Let's call the amount of 10% acid solution x liters. You formulate these mixture equations by using this expression to represent the amount of acid in the two parts being mixed together and the final solution

% concentration * amount

.10(x) + .04(3) = .08(3+x)
.10x + .12 = .24 + .08x
.02x = .12
x = 6 liters

Answer 2

Start with this:

x(10) + 3(4) = (x+3)(8)

Solve that for x, and that should get you there...