How many substances are needed to prepare a 10% salt solution?

Given:
ω (salt) = 10%

To find:
m (salt) -?
m solution (salt) -?
m (H2O) -?

Decision:
1) Everything will depend on what mass of salt must be used, or what mass of salt solution must be obtained, or what mass of water must be used;
2) m (salt) = ω (salt) * m solution (salt) / 100% = 10% * m solution (salt) / 100% = m solution (salt) / 10;
3) m solution (salt) = m (salt) * 100% / ω (salt) = m (salt) * 100% / 10% = m (salt) * 10;
4) m (H2O) = m solution (salts) – m (salts) = m (salts) * 10 – m (salts) = m (salts) * 9;
m (H2O) = m solution (salt) – m (salt) = m solution (salt) – (m solution (salt) / 10) = m solution (salt) * 9/10.