Question

Let set $M=\{x,2x,4x\}$ for any number $x$. If the average (arithmetic mean) of the numbers in set $M$ is $14$, find the value of $x$.

• A. $2$
• B. $6$
• C. $7$
• D. $10$
• E. $12$

Answer 1

The correct option is B $6$

Given set $M=$ $\{x,2x,4x\}$.
Also, average (arithmetic mean) of the numbers in set $M$ is $14$.
Then, value of $x$ will be,
$\Rightarrow \frac{x+2x+4x}{3}=14$
$\Rightarrow 7x=42$
$\Rightarrow x=6$.

Therefore, option $B$ is correct.