The sum of three numbers, each of which is greater than the previous one by 5, is 45. Find the second number.

Let the first number be x, then the second number is (x + 5) and the third number is ((x + 5) + 5). By the condition of the problem, it is known that the sum of these three numbers is equal to x + (x + 5) + ((x + 5) + 5) or 45. Let’s compose an equation and solve it.

x + (x + 5) + ((x + 5) + 5) = 45;

x + x + 5 + x + 5 + 5 = 45;

3x + 15 = 45;

3x = 45 – 15;

3x = 30;

x = 30: 3;

x = 10 – the first number;

x + 5 = 10 + 5 = 15 is the second number.

Answer. The second number is 15.