solving a mixture

Question

A scientist mixes water (containing no salt) with a solution that contains 40% salt. She wants to obtain 160 ounces of a mixture that is 20% salt. How many ounces of water and how many ounces of the 40% salt solution should she use?

Answer 1

Let x = number of ounces of water. Then 160 - x = number of ounces of 40% solution

0x + 0.40(160-x) = 0,20(160)

Solve for x.