Find the page number, which the Chaten forgot to add.

Question

Mr.Ramashankar asked his students to find the sum of all pages of their maths book.
Chaten gave the answer as 8554.
The teacher told him that he has not added one page.
Find the page number, which the Chaten forgot to add.

Answer 1

The numbers of the pages of a book orm a natural series of n elements
The formula to calculate the addition of n elements is given by :
Sum N = N x ( N+1) /2
By trial and error, we obtain that for N= 131
Sum = 131 x ( 131+1) / 2 = 8646
Then, 8646 - 8554 = 92

The answer is page number 92