Question

The sum of 9 consecutive numbers is 279. What is the sum of the first and the last number?

Answer 1

Let the first number = x

The second number would be x +1

3rd number = x +2

4th number = x +3

5th number = x+4

6th number = x+5

7th number = x +6

8th number = x +7

9th number = x+8

The sum is 279

Combine like terms in the 9 numbers to get: 9x + 36 = 279

Solve for x:

9x + 36 = 279

Subtract 36 from both sides:

9x = 243

Divide both sides by 9:

x =27

The first number is 27

The last number would be 27 + 8 = 35

The sum of the first and last would be 27 + 35 = 63