Question

The mean of four consecutive even numbers is 15. The greatest of these numbers is a1. The least of these numbers is a2.

Answer 1

X + (x + 2) + ( x + 4) + (x + 6)
-----------------------------------     = 15
                   4

4x + 12
---------    = 15
    4

Multiply by 4 on both sides

4x + 12 = 60
subtract 12 from both sides
4x = 48
divide by 4 on each side
x = 12
x + 2 = 14
x + 4 = 16
x + 6 = 18