Question

$12,a,6,8,2,14$
The average (arithmetic mean) of the numbers listed above is $6$. Calculate the value of $a$.

• A. $-36$
• B. $-6$
• C. $0$
• D. $6$
• E. $36$

Answer 1

Answer: (B)

$-6$

We know that average of a bunch of numbers is the sum of the numbers divided by how many numbers in the bunch.

We can set up an equation for the average from the given question,
$\Rightarrow \frac{12+a+6+8+2+14}{6}=6$
$\Rightarrow \frac{42+a}{6}=6$
$\Rightarrow 42+a=36$
$\Rightarrow a=-6$