The 'n' paged book
The pages of a book are numbered 1 through . When the page numbers of the book were added, one of the page numbers was mistakenly added twice resulting in the incorrect sum 1998. What was the number of the page that was added twice?
The answer is 45.
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1 solution
sum of first n pages: n(n+1)/2 <= 1998 the positive critical value is approx. 62.7159 Using Floor function we have 62 At n=62, the sum would be 1953 Thus leading us to the final equation 1953 + x = 1998 Therefore x = 45.
Note: sorry my solution has really "ugly" format. Im having a hard time using LaTeX in my phone. Also, I feel a bit lazy. Whoops