In a certain conference room each row of chairs has the same

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In a certain conference room each row of chairs has the same [#permalink]

01 Oct 2007, 22:29

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Question Stats:

86% (01:58) correct

13% (02:08) wrong

based on 4 sessions

In a certain conference room each row of chairs has the same number of chairs, 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

OPEN DISCUSSION OF THIS QUESTION IS HERE: in-a-certain-conference-room-each-row-of-chairs-has-the-same-129389.html

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Re: GMATPrep - Chairs in a conference room [#permalink]

01 Oct 2007, 23:05

slsu wrote:

In a certain conference room each row of chairs has the same number of chairs, 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

Can someone help sift through all of this seemingly superfluous information?

*editted

1st suff, n*(n-1)=72, where n is an intenger.
2nd suff, since the number of chairs in one row is the same.
R is the number of chairs in a Row
2R=17+1-----> yeilds only one solution for R=9.

thus D, initial answer (wrong) was B.

Last edited by IrinaOK on 01 Oct 2007, 23:10, edited 1 time in total.

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Re: GMATPrep - Chairs in a conference room [#permalink]

01 Oct 2007, 23:06

slsu wrote:

In a certain conference room each row of chairs has the same number of chairs, 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

Can someone help sift through all of this seemingly superfluous information?

D.

1: 72 = 8x9 sufff.
2: 2x - 1 = 17
x = 9 suff.

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Re: GMATPrep - Chairs in a conference room [#permalink]

01 Oct 2007, 23:08

GMAT TIGER wrote:

slsu wrote:

In a certain conference room each row of chairs has the same number of chairs, 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

Can someone help sift through all of this seemingly superfluous information?

D.

1: 72 = 8x9 sufff.
2: 2x - 1 = 17
x = 9 suff.

Agree!

D it is.

lesson learnt: always take notes from the stem.

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[#permalink]

02 Oct 2007, 17:55

This is how I solved it:

(1)

x^2 - x = 72.

Suff.

(2)

2x-1 = 17

Suff.

D

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Re: GMATPrep - Chairs in a conference room [#permalink]

03 Oct 2007, 11:21

slsu wrote:

In a certain conference room each row of chairs has the same number of chairs, 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

Can someone help sift through all of this seemingly superfluous information?

dont get bogged down by the words, it's a rather easy question-

ST. 1
# of chairs in a row= x
# of rows= x-1
thus total # of chairs= x(x-1)= 72
solve for x
SUFF

ST. 2
before chair was removed, there were 18 chairs in last two rows, thus # of chairs in each row= 18/2=9
SUFF

D.

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Re: In a certain conference room each row of chairs has the same [#permalink]

24 Feb 2013, 06:31

How do you get 2X - 1? for statement 2

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Re: In a certain conference room each row of chairs has the same [#permalink]

24 Feb 2013, 06:50

fozzzy wrote:

How do you get 2X - 1? for statement 2

In a certain conference room each row of chairs has the same number of chairs, and the number of rows is 1 less than the number of chairs in a row. How many chairs are in a row?

Say # of rows is R and # of chairs per row is C.
Given: R=C-1. Question: C=?

(1) There is a total of 72 chairs --> CR=72 --> C(C-1)=72 --> C=9. Sufficient.

(2) After 1 chair is removed from the last row, there is a total of 17 chairs in the last 2 rows --> C+(C-1)=17 --> C=9. Sufficient.

Answer: D.

OPEN DISCUSSION OF THIS QUESTION IS HERE: in-a-certain-conference-room-each-row-of-chairs-has-the-same-129389.html
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Re: In a certain conference room each row of chairs has the same [#permalink] 24 Feb 2013, 06:50

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In a certain conference room each row of chairs has the same

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