Determine the mass of water in which you need to dissolve 2 g of sodium nitrate to get a 10%

Determine the mass of water in which you need to dissolve 2 g of sodium nitrate to get a 10% solution for watering indoor plants.

Explanation of the solution: the main formulas used to solve this problem:
the mass fraction of the solute is found by the formula:
w = m (r.v.) / m (r-ra) * 100%, where w is the mass fraction, m (r.v.) is the mass of the solute, m (r-ra) is the mass of the solution.
mass of solution:
m (r-la) = m (r.v.) + m (r-la), where m (r-la) is the mass of the solvent, that is, water.
Suppose the mass of water is x, then:
m (p-pa) = 2 + x
w = m (r.v.) / m (solution): 0.1 = 2 / (2 + x)
Solving this equation, we find that x = 18 g.