two consecutive no's outof 1,2,3,...,n-1,n are removed. the average of remaining no's is 105/4.find n and the removed numbers

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- Jun 26th 2009, 10:29 AMabhishek aroraalgebra
two consecutive no's outof 1,2,3,...,n-1,n are removed. the average of remaining no's is 105/4.find n and the removed numbers

- Jun 26th 2009, 10:52 AMpankaj
Let the removed numbers be and

Now

On solving we have two inequalities

Since and must be an integer.

Similarly solving the inequality, and thus

Therefore,

It is only for that p is an integer.Thus

Therefore the number of pages in the book are and the removed pages are and - Jun 26th 2009, 11:01 AMabhishek arorathanks
thank you pankaj sir u are like an angel for me