Question

The sum of three consecutive numbers is eighteen. of the three numbers, what is the largest number.

Answer 1

x = 1st number
x + 1 = 2nd number
x + 2 = 3rd number

x + (x + 1) + (x + 2) = 18...combine like terms
3x + 3 = 18
3x = 18 - 3
3x = 15
x = 5

x + 1 = 5 + 1 = 6
x + 2 = 5 + 2 = 7

7 + 6 + 5 = 18
13 + 5 = 18
18 = 18 (correct)

largest number is 7