Evaporated 150 g of a 15% sugar solution. How many grams of sugar is there in the cup after evaporation?

In the condition of the problem, the total mass of water and sugar is given – 150 g, as well as the mass fraction of sugar in the solution – 15%. Knowing this and using the formula below, we can find the mass of sugar in the original solution.

W = msugar / msugar + solvent * 100%

Let the sugar mass be x.

15 = x / 150 * 100

x = 22.5 g

mwater = 150 – 22.5 = 127.5 g.

Thus, when the solution was evaporated, 127.5 g of water evaporated from the cup and 22.5 g of sugar remained.