Question

The mean of four consecutive even numbers is 15

Answer 1

I suppose you have to find the four numbers. If $x$ is the smallest of the four, then the next three numbers are $x+2$, $x+4$, and $x+6$. The mean is 15, so

$\dfrac{x+(x+2)+(x+4)+(x+6)}4=\dfrac{4x+12}4=15$
$\implies x+3=15$
$\implies x=12$


So the four numbers are 12, 14, 16, and 18.