Intermediate Page Numbers - XP Math - Forums

 XP Math - Forums Intermediate Page Numbers

05-22-2012   #1
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Page Numbers

A total of 642 digits was used in numbering the pages of a book. How many pages did the book contain?

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05-22-2012   #2
JosePereira11

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Quote:
 Originally Posted by noreply A total of 642 digits was used in numbering the pages of a book. How many pages did the book contain?
Hi noreply. First i must congratulate you by your activity in xp maths along with MAS1 in what concerns putting and resolving problems.

This one is easy but funny. =)
So, first we suppose that all the pages are numbered.
Then:
1-9 page its 9 digits
10-99 page its 180 digits (99-9=90 ; 90*2=180)

We stop here. We already have 9+180 digits = 189 . We need 642-189=453 ;
453/3 = 151

151+99=250

Result: 250 pages.
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08-13-2012   #3
jorgea
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Page Numbers

250 pages. Thanks for creating this challenge question here at http://www.xpmath.com

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