The atomic mass of an atom is the sum of: A protons and electrons
B protons and neutrons
C electrons and neutrons

The equation to find the percentage by mass of a solution is:

(Mass of solute/mass of solution) x 100 = percentage by mass

So, let's identify the variables.

Mass of solute: 22g

Mass of solution: 112g

The reason that the solution is 112g and not 90g is because the solution needs to include the mass of the solute and solvent, meaning 90 + 22 is the mass of the solution.

(22/112) x 100 = 19.6%