Question

If the mean of $x,x+2,x+4,x+8$ is $20$ find $x$.

Answer 1

Mean$=\frac{x+x+2+x+4+x+8}{4}=20$

$\Rightarrow \frac{4x+14}{4}=20$

$\Rightarrow 4x+14=80$

$\Rightarrow 4x=80-14=66$

$\Rightarrow x=\frac{66}{4}=\frac{33}{2}=16.5$

$\therefore x=16.5$