How many grams of salt and how many milliliters of water do you need to take to prepare 250 g of its 20% solution?

The weight of the solution is 250 grams;

To find the weight of the salt, it is necessary to multiply its mass fraction by the weight of the solution.

m salt = 250 x 0.2 = 50 grams;

To find the mass of water, subtract the weight of the salt from the weight of the solution:

m water = m solution – m salt = 250 – 50 = 200 grams;

Check: 200 + 50 = 250;

The sum of the found weights of salt and water gives the initial weight of the solution.