Percent chance please

Question

8 gal. of a 90% acid solution was mixed with 10 gal. of pure water. Find the concentration of the new mixture.

Answer 1

The volume of the finished solution will be 18 gal.

Write a concentration*volume equation as follows: .9*8 + 1*10 = x*18

You solve it from here.

Remember the answer for x will be a decimal fraction which needs to be multiplied by 100 to make a %.