In the alloy of tin and copper with a mass of 16 kg, 2 kg of tin was added. After that, the content of tin

In the alloy of tin and copper with a mass of 16 kg, 2 kg of tin was added. After that, the content of tin in the alloy increased by 5%. How much tin was in the alloy initially?

Let’s take the amount of tin as x initially, then:

x / 16 * 100 – initial concentration;

x + 2 is the amount of tin after adding 2 kg;

(x + 2) / 18 * 100 – final concentration.

We get the equation:

(x + 2) / 18 * 100 – x / 16 * 100 = 5;

(x + 2) / 9 – x / 8 = 5/50 = 0.1;

8 * (x + 2) – 9x = 0.72;

x = 16 – 0.72;

x = 15.28.

Answer: The amount of tin in the original alloy was 15.28 kg.