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How many odd integers are greater than the integer x and les

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gmat blows
 Post subject: How many odd integers are greater than the integer x and les
 Post Posted: Sat Jun 14, 2008 11:21 pm 
How many odd integers are greater than the integer x and less than the integer y?
1) There are 12 even integers greater than x and less than y
2) there are 24 integers greater than x and less than y

This is from the GMATPrep 1. I thought this was a Ctrap and chose A - I honstly, have no clue how to approach this problem. any insight will be appreciated. thanks.
OA: B
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Maverick
 Post subject:
 Post Posted: Sun Jun 15, 2008 5:07 am 
How many odd integers are greater than the integer x and less than the integer y?
1) There are 12 even integers greater than x and less than y
2) there are 24 integers greater than x and less than y

.......x........................y.............

(1) If x and y are both odd: x.(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e).y. 11 odds.

But if x is odd and y is even: x.(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).y. Look at the last odd. 12 odds.. Insufficient.

(2) There are even number of integers between x & y. It is possible only when there are 12 even & 12 odd integers between x & y.[/b]
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RonPurewal
 Post subject:
 Post Posted: Wed Jun 18, 2008 5:09 am 
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ManhattanGMAT Staff


Posts: 7146
Maverick wrote:
How many odd integers are greater than the integer x and less than the integer y?
1) There are 12 even integers greater than x and less than y
2) there are 24 integers greater than x and less than y

.......x........................y.............

(1) If x and y are both odd: x.(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e).y. 11 odds.

But if x is odd and y is even: x.(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).(e.o).y. Look at the last odd. 12 odds.. Insufficient.

(2) There are even number of integers between x & y. It is possible only when there are 12 even & 12 odd integers between x & y.[/b]


well played.
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Sam
 Post subject:
 Post Posted: Thu Nov 27, 2008 10:36 am 
Hi Guys,
I have a question...The given statement (2) never says that the 24 integers between x and y are consecutive integers right? So all the 24 integers can be even or all can be odd. In this case it can be 24 odds or 24 evens. And yes if the statement said that the 24 integers are consecutive then your answer is correct...
Any thoughts??
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RonPurewal
 Post subject:
 Post Posted: Sat Nov 29, 2008 7:43 am 
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ManhattanGMAT Staff


Posts: 7146
Sam wrote:
The given statement (2) never says that the 24 integers between x and y are consecutive integers right?


it doesn't have to. since the statement is counting all integers between x and y, they must be consecutive.

if you can find 24 integers between x and y, with "holes" between some of them (i.e., they're not all consecutive), then the "holes" also represent integers between x and y. therefore, there would actually be more than 24 integers between x and y.

remember: if a statement says "there are N of these things", then that means all of these things.
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