Question

The mean of 9 terms is 15. If one new term is added and mean become 16, then the value of new term is

• A. $23$
• B. $25$
• C. $27$
• D. $30$

Answer 1

The correct option is B $25$

Let $x_1,x_2,....x_9$ be the observations.
$\overline{x}=\frac{x_1+x_2+...+x_9}{9}$
$\Rightarrow x_1+x_2+...+x_9=135$
Now, let $x_{10}$ is added
New mean $=\frac{x_1+x_2+....+x_9+x_{10}}{10}$
$16=\frac{135+x_{10}}{10}$
$\Rightarrow x_{10}=25$