The total mass of three pieces of granite is 156 kg. A piece of gray granite is 18 kg heavier than a piece of red and a piece

The total mass of three pieces of granite is 156 kg. A piece of gray granite is 18 kg heavier than a piece of red and a piece of red is 15 kg lighter than a piece of white. Find the mass of a piece of red granite.

The solution of the problem:

1. Let’s assume that a piece of red granite weighs x kg.

2. Then a piece of gray granite weighs (x + 18) kg.

3. A piece of white granite weighs (x + 15) kg.

4. Let’s compose and solve the equation.

x + (x + 18) + (x + 15) = 156;

3x + 18 + 15 = 156;

3x + 33 = 156;

3x = 156 – 33;

3x = 123;

x = 41.

Answer: The mass of a piece of red granite is 41 kilograms.