What mass fraction of salt will be obtained if 60 g of salt is dissolved in 140 g of water?

Let us analyze the condition that we know the mass fraction (w) of the salt will be obtained if 60 g of salt (mr) dissolves in 140 g of water (mr-la).
w = (mr.v / mr-ra) * 100%.
mr-ra = mr.v + mr-la.
From the condition, we know everything for calculating the mass of the solution (mr-pa).
mr-ra = 140 + 60 = 200 (g).
Now you can calculate the mass fraction:
w = (60/200) * 100% = 30%
Answer: the mass fraction of salt that will turn out if 60 g of salt dissolves in 140 g of water is 30%.