Calculate the mass of sugar to be dissolved in 1 liter of water to make a 20% solution.

Water has a density of 1 gram / cm3 = 1 kilogram / liter;

Therefore, the mass of one liter of water is 1000 grams;

It is necessary to obtain a solution in which sugar occupies 20% of the mass.

Accordingly, in this solution, water will occupy 80% of the mass.

Let’s find the mass of the solution through the mass of water and its fraction.

It will be 1000 / 0.8 = 1250 grams;

The sugar mass will be: 1 250 – 1 000 = 250 grams;