The sum of three numbers is 69. The first number is one less than the second number. The third number is seven more than the second number. What are the three numbers?

x-1 + x + x+7 = 69

mommy

To solve this problem, let's first assign variables to the three unknown numbers.

Let's say the second number is x.

The first number is one less than the second number, so it can be expressed as x - 1.

The third number is seven more than the second number, so it can be expressed as x + 7.

According to the problem, the sum of these three numbers is 69.

So, we can write the equation:

(x - 1) + x + (x + 7) = 69

To solve this equation, we need to combine like terms:

3x + 6 = 69

Now, isolate the variable:

3x = 69 - 6
3x = 63

Divide both sides of the equation by 3:

x = 21

Now that we have the value of x, we can substitute it back into the expressions we set up earlier to find the other two numbers.

The first number is x - 1, which is 21 - 1 = 20.

The third number is x + 7, which is 21 + 7 = 28.

So, the three numbers are 20, 21, and 28.