The solution contains 15% salt. if you add 150 g of salt, then the solution will contain 45% salt.

The solution contains 15% salt. if you add 150 g of salt, then the solution will contain 45% salt. Find the mass of salt in the original solution.

Let’s denote by the unknown variable x gram – the mass of the initial solution,
0.15x grams is the mass of salt in the initial solution.
0.15x + 150 grams – there was a mass of salt in the new solution.
x + 150 grams – the mass of the new solution has become.
0.45 * (x + 150) grams is the mass of salt in the new solution.
We compose equality:
0.15x + 150 = 0.45 * (x + 150);
0.45x + 67.5 = 0.15x + 150;
0.3x = 82.5;
x = 275 grams the mass of the initial solution,
0.15 * 375 = 41.25 grams is the mass of salt in the initial solution.