GMAT Prep

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GMAT Prep

by mna123 » Sun Jun 14, 2009 9:17 am
How come answer is C , I believe it is D

You can solve eq for r and s and put in line eq to check if it lies on line ....
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Source: — Data Sufficiency |

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by raleigh » Sun Jun 14, 2009 10:55 am
y=3x+2 containing the point (r,s) means that s = 3r + 2.

(1) Tells us that 3r + 2 - s = 0 OR 4r + 9 - s = 0.

3r + 2 - s = 0 gives us s = 3r + 2. But this can also be satisfied from s = 4r + 9 (from 4r + 9 - s = 0)

So this is not sufficient.

(2) Similarly, we get 4r - 6 - s = 0 OR 3r + 2 - s = 0. Solving for s we get s = 4r - 6 OR s = 3r + 2

So this is not sufficient.

(1)+(2) s = 3r + 2 is the only factor that satisfies BOTH 1 and 2 so s = 3r + 2.

So the answer is C.