Cory mixes x liters of a 20% alcohol solution with another amount of a 40% alcohol solution. If the total volume of the mixture is 15 liters, then the mixture contains how many liters of pure alcohol.

Question

You should be typing an algebraic expression in the variable xx. You can type it in any form.

Answer 1

In xL of 20% solution we have 0.2x L of pure alcohol. If we add yL of a 40% solution we are adding 0.4y L of pure alcohol and we have x+y=15L. The total amount of pure alcohol is 0.2x+0.4y. Since y=15-x, this amount is 0.2x+0.4(15-x)=0.2x+6-0.4x=6-0.2x in terms of x.