75 g of salt was dissolved in 150 g of water. Determine the mass fraction of salt in the resulting solution.

To find out the mass fraction of a substance in a solution, it is required to add the masses of the constituent parts of this solution.
1) 150 + 75 = 225g. (solution weight)
Then you need the mass of the component, the mass fraction of which you need to find out in the resulting solution, divided by the mass of the resulting solution.
2) 75/225 = 0.33 or 33% if rounded.
You can also find out the proportions of the components. That is, if the salt contains 1/3 of the mass of the solution, then the salt is mixed with water in a 1: 2 ratio.
3) Universal formula: mass fraction of component 1 = (mass of component 1 / (mass of component 1 + mass of component 2)) * 100%