Question

The average of first $50$ natural numbers is

• A. $21.15$
• B. $25.5$
• C. $25$
• D. $12.25$

Answer 1

Answer: (B)

The correct option is B $25.5$

The first $50$ natural numbers are $1,2,3,...,50$

We know that, the sum of first $n$ natural numbers is $\frac{n(n+1)}{2}$

Therefore, sum of first $50$ natural numbers is $=\frac{50\times 51}{2}=25\times 51=1275$

We know that, Average of $n$ number of observations $=\frac{\text{sum of all the observations}}{\text{Number of observations}}$

Here the number of observations are $50$.

$\Rightarrow$ Average of first $50$ natural numbers

$=\frac{1275}{50}$

$=25.5$

Hence, the average of first $50$ natural numbers is $25.5$