Question

The mean of four consecutive even numbers is 15.

Answer 1

let first number be x so the numbers will be  x , x+2 , x+4 , x+6 so by mean we get  (x + x + 2 + x + 4 + x + 6) / 4 = (4x+12)/4 = [ 4 ( x + 3 ) ] / 4 (1) here numerator and denominator 4 will be cancelled so we get x + 3 = 15 x = 15 - 3 = 12 so the numbers are 12 ,14 ,16 , 18