Question

find n if sum of first n no. Is n^/81

Answer 1

Sum of n odd no.s=n^2

mEan =n^2/n=n

N^2=81n

N=81

Answer 2

sum of n ibb no.s = n^2 .

mean = n^2 / n =n .

n^2 = 81 n.

n= 81

this is answer of your question.