There are 5 liters of 20% salt solution. Two liters of the solution were poured, then 1 liter

There are 5 liters of 20% salt solution. Two liters of the solution were poured, then 1 liter of 50% salt solution was added. What is the concentration of salt in the resulting solution?

There were 5 liters of a 20% salt solution, 2 liters were poured, which means that 3 liters of a 20% salt solution remained.

0.2 * 3 = 0.6 liters – the mass of salt in this solution.

Then 1 liter of 50% salt solution was added.

It contains 0.5 liters of salt.

So 1 + 3 = 4 liters – the mass of the new solution.

0.6 + 0.5 = 1.1 liters – the mass of salt in the new solution.

1.1 / 4 * 100% = 27.5% – the concentration of salt in the new solution.