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Trivial number line

Expert replies
by kanha81 » Mon Apr 20, 2009 12:15 pm
If s and t are two different numbers on the number line, is s+t = 0?

1) The distance between s and 0 is same as the distance between t and 0

2) 0 is between s and t
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Source: — Data Sufficiency |

by Sher1 » Mon Apr 20, 2009 1:32 pm
Ans C
We need to show that s+t = 0 only possible if one is +ve and other is the -ve value of it. or s=-t

St 1
s=t or s=-t

St 2
Don't know if they are same values

St1 and St2

s=-t
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by mals24 » Mon Apr 20, 2009 2:06 pm
I'll go with A

Given: s and t are 2 different numbers.
Asked: is s+t = 0 or is s = -t?

St 1: s cannot be equal to t (since they are 2 different numbers)
So the only option left is s = -t.

So St 1 is suff.

St 2: it just means that the 2 numbers have opposite signs.

So St 2 is insuff.
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by iamcste » Mon Apr 20, 2009 3:20 pm
IMO A

key is to understand s and t are different nos.

same explanation as mals24
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by ketkoag » Wed Apr 22, 2009 2:15 am
by 1 distance of s and 0 will be equal to 0 and t only when 0 is the midpoint of both the nos.
hence s = -t.
suff.

2. 0 can be anywhere between s and t. hence insuff.

IMO A
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by bonetlobo » Mon May 11, 2015 4:06 am
Attempted this question today. I like the title "Trivial number line".

As per (1), if distance of s and t from 0 is the same (and it is given that s and t are "different" numbers), then it has to be the case that one is positive and the other is negative and they are equi-distance from 0.
=> s + t = 0
Sufficient.

As per (1), 0 is between s and t. This obviously does not tell us anything about the actual values. For example, it is possible that s = 5, t = -1; or it is possible that s = 5, t = -5.
Insufficient.

Hence, A.
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by Eli@Prep4GMAT » Tue May 26, 2015 1:19 pm
A is correct here. Remember to pay attention to every bit of information you're given in the question stem; even little phrases like "two different numbers" can completely change the solution to a DS problem.
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