To 200 grams of a 20% ethanol solution was added 150 grams of a 30%

To 200 grams of a 20% ethanol solution was added 150 grams of a 30% solution of the same substance. Calculate the mass fraction of ethanol in the resulting solution.

Ethanol formula: C2H5OH.
1) 200 * 20/100 = 40g – the mass of the solute ethanol in its solution (first solution).
2) 150 * 3/100 = 4.5 g – the mass of the solute ethanol in its solution (second solution).
3) 40 + 4.5 = 44.5 g – the mass of the solute ethanol in the resulting solution (after merging the two solutions).
4) 200 + 150 = 350g – the mass of the entire solution after draining.
5) 44.5 / 350 * 100 = 12.7% – the answer.
The mass fraction of a substance is found by dividing the mass of the solute by the mass of the solution and multiplying by one hundred percent.