In the xy plane, line x goes through the point (a,1) and lin

Question

In the xy plane, line x goes through the point (a,1) and line y goes through the point (1,b). If the lines x and y intersect, is the slope of x bigger than the slope of y?

(1) a > b
(2) |a| > |b|

Appreciate if someone could help with the following question. Appreciate also referrals/links to similar questions to digest the subject/theory behind this better. Thanks.

Bunuel · Accepted Answer

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Blackishmamba · Answer

Hope the solution below helps

Posted from my mobile device

mau5 · Answer

From F.S 1, Assume a=1,b=0.

From the graph,line y is represented as blue and has a slope of 0.Thus, For the green line,which passes through (1,1), the slope is negative and thus less than the slope of line y

For the red line, which passes through (1,1), the slope is positive and more than the slope of line y.Insufficient.

From F.S 2, assuming the same set as a=1,b=0, we have the same result as above.

Taking both together , we have nothing new to add.

E.

thangvietnam · Answer

great explanation above
we should use algebra not drawing for this type, because doing so is quicker.

Hero8888 · Answer

How long will it take for you to make all this algebra? Drawing and answering took 3 min, and I got the right answer.
Althought the question can be approached logicaly: to know the slope of any line we have to know at least 2 points.

GMATBusters · Answer

If the lines x and y intersect  ,  is the slope of x bigger than the slope of y?

Any two lines in the plane will always intersect unless they are parallel( have equal slope), it does not matter which has bigger slope . 
 
 So, it is not possible to answer, which has bigger slope

Answer E

CEdward · Answer

Best bet here is to draw it?

In the xy plane, line x goes through the point (a,1) and line y goes through the point (1,b). If the lines x and y intersect, is the slope of x bigger than the slope of y?

(1) a > b

Suppose (a,1) = (4,1) and (1,b) = (1,-1)

We can draw a horizontal line running through (4,1) and any line with a slope running through (1,-1). Flip the lines.

Insufficient.

(2) |a| > |b|

Same use case as above.

Insufficient.

Answer is E.

HC1993 · Answer

For this question, I think we need to understand the basic idea when we draw a line in coordinate geometry.

for every slope, we need to identify two points that create a line. One could be the intersecting point such as (a,1) and (1,b) but what about the other point??? is its origin (0,0) or any specific y intercept??
We don't know that.

Hence, answer E

Can,Will · Answer

It took me 30 secs. May be my logic and reasoning is stupid but like to share. 
we need point of intersection to get the slopes of each line. Even we make equations for lines we have not enough information to get the point of intersection.So can not determine the slope using both the statements.
even by using formula,slope= -y intercept/x intercept , we are not able to determine the slope

above reasoning may sound stupid or not, I get the answer in 30sec

quiaitaque · Answer

GMATinsight   EgmatQuantExpert

Is my thought process Right. WE cant determine whether Slope of Line X > Line Y or not since we need at least 2 coordinate poitns to make such a judgement.

Bunuel · Answer

When combining the statements, all we really know is the relative position of where the first line intersects y = 1 and where the second line intersects x = 1. For example, the first line might intersect y = 1 at (3, 1), and the second line might intersect x = 1 at (1, -2). From this, we cannot conclude which line has the greater slope, since either could be steeper. In general, yes, we need two points to determine a line’s slope. But I wouldn’t generalize it as you said, because sometimes we may be given additional information, such as an equation or another constraint, that would allow us to determine the slope. https://gmatclub.com/forum/download/file.php?id=85936 GMAT-Club-Forum-tpynf02q.png

In the xy plane, line x goes through the point (a,1) and lin

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