number line

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number line

by gmat740 » Mon Jun 15, 2009 8:27 am
----r---- s---- t---
On the number line shown, is zero halfway between r and s?
1). s is to the right of zero
2). the distance between t and r is the same as the distance between t and -s.
[spoiler]OA-C
IMO-B[/spoiler]

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Re: number line

by jakesing » Mon Jun 15, 2009 8:43 am
gmat740 wrote:----r---- s---- t---
On the number line shown, is zero halfway between r and s?
1). s is to the right of zero
2). the distance between t and r is the same as the distance between t and -s.
[spoiler]OA-C
IMO-B[/spoiler]
I almost made the same mistake as you did, but consider this:

r=-5, s=-3, t=-1. -s=3, so this would work with 2, but would not be sufficient to answer the question.

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Re: number line

by Vemuri » Mon Jun 15, 2009 10:46 pm
Good question Karan. I got tricked as well.

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by ssmiles08 » Tue Jun 16, 2009 6:18 am
Can someone explain this in detail please...I am having trouble understanding the concept here.

taking all numbers to be positive I get -r = s. After that I seem to derail :(

Thanks

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by Vemuri » Tue Jun 16, 2009 6:47 am
ssmiles08 wrote:Can someone explain this in detail please...I am having trouble understanding the concept here.

taking all numbers to be positive I get -r = s. After that I seem to derail :(

Thanks
We basically need to find out if '0' comes in between r & s on the number line.

The question stem does not say that r,s & t are positive integers. So, given the information in Statement 2, if t=-1 s=-3 & r=-5, then -s=3. The distance between t & r is 4 & the distance between t & -s is also 4. But 0 is not between r & s. Now, if we consider t=1, s=3 & r=5, then -s=-3. The distance between t & r is 4 & the distance between t & -s is also 4. But in this condition 0 comes in between r & s. So, this statement alone is not sufficient.

Both statements combined allows us to answer the question. Hence C. Hope this helps you get back on track :-)

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by ssmiles08 » Tue Jun 16, 2009 7:49 am
Vemuri wrote:
ssmiles08 wrote:Can someone explain this in detail please...I am having trouble understanding the concept here.

taking all numbers to be positive I get -r = s. After that I seem to derail :(

Thanks
We basically need to find out if '0' comes in between r & s on the number line.

The question stem does not say that r,s & t are positive integers. So, given the information in Statement 2, if t=-1 s=-3 & r=-5, then -s=3. The distance between t & r is 4 & the distance between t & -s is also 4. But 0 is not between r & s. Now, if we consider t=1, s=3 & r=5, then -s=-3. The distance between t & r is 4 & the distance between t & -s is also 4. But in this condition 0 comes in between r & s. So, this statement alone is not sufficient.

Both statements combined allows us to answer the question. Hence C. Hope this helps you get back on track :-)
I see it!! thank you! :)