slope DS

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Source: — Data Sufficiency |

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by clock60 » Mon Dec 20, 2010 3:30 pm
if i got the problem right the answer seems like C
(1) y(2)=2, 2m+n=2 to me insuff
(2) y(3)=-4, 3m+n=-4 also 2 unknowns
both, solving two equations gives: m=-6

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by Night reader » Mon Dec 20, 2010 3:32 pm
clock60 wrote:if i got the problem right the answer seems like C
(1) y(2)=2, 2m+n=2 to me insuff
(2) y(3)=-4, 3m+n=-4 also 2 unknowns
both, solving two equations gives: m=-6
correct, OA is C

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by Rahul@gurome » Mon Dec 20, 2010 8:10 pm
Night reader wrote:If y = mx + n is a line in the (x, y) plane, what is the slope m?
  • (1) y(2) = 2
    (2) y(3) = -4
Just recall that to determine the slope of a certain straight line we must have at least two points on the line. Here statement 1 and 2 each provides one such point on the line. Thus both of them are insufficient. Combining them we have two points and thus we can easily determine the slope.

The correct answer is C.
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