Question

If the Arithmetic mean of the numbers $27,23,x-4,x+4,15,3$ and $7$ is $13$, then find the value of $x.$

Answer 1

Arithmetic mean of the given numbers is $13$, so

$\frac{27+23+x-4+x+4+15+3+7}{7}=13$

$\frac{75+2x}{7}=13$

$75+2x=91$

$2x=16\Rightarrow x=8$

Value of the $x$ is $8$