Rohit prepared a project report of 225 pages, where content and page numbers are printed on one side

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28 Mar 2022 Arithmetic

Rohit prepared a project report of 225 pages, where content and page numbers are printed on one side of a paper. Due to printing mistake one page was missing and Rohit sum up all page numbers to 25268. Which among the following is a missing page ?

OPtion

1) 137
2) 175
3) 159
4) 197
5) 169
6) 119
7) 157
8) 183
9) 154
10) None of these

Solution

Page numbers are 1,2,3,......,225
Sum of first n numbers = n(n+1)/2
.'. Sum of 225 pages = 225x226/2 = 25425
Given, sum of page numbers excluding missing page = 25268
Therefore, missing page number = 25425 - 25268 = 157

Correct Option: 7 Best Solution (4)