Question

first 21 natural numbers average​

Answer 1

Answer:

Step-by-step explanation:

1 - Average= (sum of first 21 natural numbers) / 21

2 - sum of first 21 natural number = n/2(2a+(n-1) d) [Arithmetic progression formula

3- Average= 231/21

=11(ans.)

Answer 2

Answer:

We should find the average value of first 21 natural numbers.

Answer: Average of 21 Natural Numbers $=11$

Step-by-step explanation:

From the given question,

• Natural numbers should start from $1,2,3,4,5,6..........$
• So that we can find the average of first 21 natural numbers.

Formula:

      Average of n Natural Numbers $=\frac{sum \hspace{1mm}of\hspace{1mm} n \hspace{1mm}natural\hspace{1mm} numbers}{n}$

           Sum of n natural numbers $=\frac{n(n+1)}{2}$

     Average of n Natural Numbers  $=\frac{\frac{n(n+1)}{2}}{n}$

                                                          $={\frac{n(n+1)}{2n}$

• Cancel n in the numerator and denominator.So that,

     Average of n Natural Numbers  $={\frac{n+1}{2}$

• Here n is the given number of natural number. For the given question n = 21.

      Average of n Natural Numbers $={\frac{n+1}{2}$

      Average of 21 Natural Numbers $={\frac{21+1}{2}$

                                                            $={\frac{22}{2}$    

      Average of 21 Natural Numbers $=11$