Mixture...1

[nycmathguy]

John has 20 ounces of a 20% of salt solution. How much water should he evaporate to make it a 30% solution?

Let me see.

Let w = how much water John should evaporate

20(0.20) - w = 0.30(20 - w)

Correct set up?

 

[MathLover1]

Since it asks the amount of water to be evaporated (subtracted) the solutions must be in terms of water.
20% salt is 80% water
30% salt is 70% water

(0.80)(20) - w = (0.70)(20 - w)

 

[nycmathguy]

Since it asks the amount of water to be evaporated (subtracted) the solutions must be in terms of water.
20% salt is 80% water
30% salt is 70% water

(0.80)(20) - w = (0.70)(20 - w)

What words in the problem stated that 80% water and 70% water must be applied?