Question

if the mean of first N natural numbers is 11 then find the value of N​

Answer 1

Answer:

Hello !

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Mean = sum of n natural numbers / n 

          = n(n+1) / 2n 

ATQ , 

n(n+1) / 2n = 11

n²+ n = 22n

n² - 22n + n = 0 

n² - 21 n = 0

n(n-21) = 0 

n = 0 

or n = 21 

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hope it helps you.....

Answer 2

Sigma x/n

=

1+2+3+4+5+6+7+8+9+10+11/11

=

66/11

=

6

therefore, the mean value is 6