If the arithmetic mean of the first natural numbers is 191,then the sum of the digits in n is

answer = 12

Arithmetic Mean = Sum of observations / Number of observations Given, Arithmetic mean of first n natural numbers = 191 Sum of first n natural numbers = n(n+1)/2 Arithmetic Mean = ( n(n+1)/2)/n 191 = (n(n+1)/2)/n 191n = n(n+1)/2 191n = (n^2+n)/2 382n = n^2+n 381n = n^2 n = 381( Number of Observations) Sum of the first n natural numbers = n(n+1)/2 = 381(381+1)/2 =72,771 Sum of the digits in n = 72,771