coordinate

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coordinate

by sud21 » Thu Jan 12, 2012 4:31 am
Is line A's slope less than B's slope?
1). A and B intersect at point P (10,1)
2). the y-intercept of A is greater than that of B.
Source: — Data Sufficiency |

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by sud21 » Tue Jan 31, 2012 7:51 pm
St.(1) If one of the points through which the line passes and the slope of the line is known, then the equation of the line is y-y1=m(x-x1). Here we know the point but don't have the slope.Not sufficient.

St.(2) If the x intercept a and y intercept b is given, then the equation of the line is x/a+y/b=1. We don't know what are the both intercepts. Not sufficient.

C or E.

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by bajjuri6 » Thu Feb 02, 2012 1:09 pm
if Y = MX + C is the equation of the line with slope M and y-intercept C, M = (Y-C)/X

As C increases, M decreases.

IMO B

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by MakeUrTimeCount » Thu Feb 02, 2012 1:59 pm
@bajjuri6:

Y intersect means X = 0
So Y intersect gives the value of C. It does not says anything about Slope.


1). A and B intersect at point P (10,1)
Does not tell anything about Slope. Insufficient.

2). the y-intercept of A is greater than that of B.
Tells about the constant of the equation of line. Again no slope. Insufficient.


Using Both,
We know that line A passes through (0,C1) and line B passes through (0,C2) where C1 > C2.
Hence,
Slope of line A: (C1 -1)/(0-10) = 0.1 (1- C1)
Slope of line B: (C2 -1)/(0-10) = 0.1 (1- C2)

As C1 > C2 => 1-C1 < 1-C2
Line A has lesser slope.

Ans: C

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by Seyitbek » Thu Feb 02, 2012 10:33 pm
Definitely the answer is C.
A: does not provide any information. infinite solutions, provides no definitive answer.
B: No definitive answer slope is not measures by Y intercept. Slope is Change in Y over Change in X.

So, possibilities are C or E
C: Together we know that B's y intercept is higher and they intersect at same point. Therefore, its slope is less. SUFFICIENT