chairs

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chairs

by Xbond » Thu Aug 20, 2009 1:05 am
In a certain conference room each row of chairs has the same number of chair, and the number of rows is 1 less than the number of chairs in a row. How many chairs are in a row?

(1) There is a total of 72 chairs.
(2) After 1 chair is removed from the last row, there is a total of 17 chairs in the last 2 rows.
Source: — Data Sufficiency |

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by tohellandback » Thu Aug 20, 2009 1:39 am
IMO D
total rows=r
total chairs per row=C
r=C-1

1) C(C-1)=72
C=9
SUFF

2)C+C-1=17
C=9
SUFF
The powers of two are bloody impolite!!

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by Xbond » Sat Aug 22, 2009 12:04 am
many thks