Gmat prep : Line Sum

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Gmat prep : Line Sum

by Skywalker » Tue Oct 05, 2010 1:55 pm
Hi,

I really could not figure this one...I know its simple but can't get around it. The [spoiler]OA = C[/spoiler].
Please let me know the solution steps...


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by Rahul@gurome » Tue Oct 05, 2010 5:39 pm
Since the point (r, s) lies on the line y = 3x + 2, so s = 3r + 2 or the question becomes: Is s = 3r + 2?

(1) (3r + 2 - s)(4r + 9 - s) = 0 implies either 3r + 2 - s = 0 or 4r + 9 - s = 0, which implies s = 3r + 2 or s = 4r + 9
No unique value of s.
So, (1) is NOT SUFFICIENT.

(2) (4r - 6 - s)(3r + 2 - s) = 0 implies either 4r - 6 - s = 0 or 3r + 2 - s = 0. Again no unique value of s.
So, (2) is NOT SUFFICIENT.

Combining (1) and (2), we get a unique value of s = 3r + 2

[spoiler]The correct answer is (C).[/spoiler]
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