DS Question:
On the number line, the distance between point A and point C is 5 and the distance between point B and C is 20. Does point C lie between point A and point B?
1. The distance between point A and point B is 25.
2. Point A lies to the left of B.
please help
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- codesnooker
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Answer: (D). Both the statements are alone sufficient.
Solution:
Check the attached image.
On the number line there are only two conditions where B can lie, marked as B and B'.
As first statement state: distance between A and B is 25 => B' not possible as distance between A and B' is only 15 which contradicts 1st statement. => C lies between A and B.
Statement 2 state, Point A lies left to B => C lies between A and B.
Image is self explanatory, as B' is not possible at all with any one of the mentioned statement
Solution:
Check the attached image.
On the number line there are only two conditions where B can lie, marked as B and B'.
As first statement state: distance between A and B is 25 => B' not possible as distance between A and B' is only 15 which contradicts 1st statement. => C lies between A and B.
Statement 2 state, Point A lies left to B => C lies between A and B.
Image is self explanatory, as B' is not possible at all with any one of the mentioned statement
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- Stuart@KaplanGMAT
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I agree that statement (1) is sufficient.codesnooker wrote:Answer: (D). Both the statements are alone sufficient.
Solution:
Check the attached image.
On the number line there are only two conditions where B can lie, marked as B and B'.
As first statement state: distance between A and B is 25 => B' not possible as distance between A and B' is only 15 which contradicts 1st statement. => C lies between A and B.
Statement 2 state, Point A lies left to B => C lies between A and B.
Image is self explanatory, as B' is not possible at all with any one of the mentioned statement
However, for statement (2), why couldn't it go:
C----5------A-------------15--------------B
to get a "no" answer?
In fact, since we don't have any directional info other than statement (2), how can it possibly matter if A is to the left of or to the right of B? Even in your sketch for statement (1) it could have gone:
B----------20------------C----5----A
or
A-----5----C------------20---------B
(1) is sufficient, but (2) isn't: choose (b).
Stuart Kovinsky | Kaplan GMAT Faculty | Toronto
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- codesnooker
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