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OG practice coordinate plane problem

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OG practice coordinate plane problem

by Redhorsep » Mon Oct 10, 2011 6:44 am
Hi,

Can someone please show this problem on a graph? It's hard to visualize the solution just by reading the OG explanation. I guessed the best approach here would be to visualize it instead of plugging it into the y=mx+b formula right? Thanks in advance!

****
In the xy plane, if line k has negative slope and passes through the point (-5, r), is the x intercept of line k positive?

1) The slope of line k is -5
2) r>0
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Source: — Data Sufficiency |
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by nandy1984 » Mon Oct 10, 2011 7:17 am
Redhorsep wrote:Hi,

Can someone please show this problem on a graph? It's hard to visualize the solution just by reading the OG explanation. I guessed the best approach here would be to visualize it instead of plugging it into the y=mx+b formula right? Thanks in advance!

****
In the xy plane, if line k has negative slope and passes through the point (-5, r), is the x intercept of line k positive?

1) The slope of line k is -5
2) r>0

Image

Here you see all the lines with arrows pointing down are the lines having the negative slope. Negative slope means there is a decrease in the value of y for the increase in the value of x.
From statement 1) lets pick a line having negative slope of -5 say the blue line. Since we have no information about the r that is y intercept it can line on x=-5 line from r = -infinity to + infinity so the line might touch the x axis at infinite locations so this is not sufficient.
Statement 2) given r>o but still there is a lot of space from 0 to infinity so still we cannot have one single value of x - intercept. We also dont know the slope sp there is another infinite combinations of these. so insufficient.
Combining the statements will lead to the Statement 20 ie r>0 and slope m = -5 but since we dont know the value of r exactly there will be infinite values of x intercept....

HOPE U UNDERSTOOD...THANKS.....
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Master | Next Rank: 500 Posts
Posts: 105
Joined: Fri Nov 05, 2010 8:29 pm
Thanked: 4 times

by nandy1984 » Mon Oct 10, 2011 7:19 am
Redhorsep wrote:Hi,

Can someone please show this problem on a graph? It's hard to visualize the solution just by reading the OG explanation. I guessed the best approach here would be to visualize it instead of plugging it into the y=mx+b formula right? Thanks in advance!

****
In the xy plane, if line k has negative slope and passes through the point (-5, r), is the x intercept of line k positive?

1) The slope of line k is -5
2) r>0

Image

Here you see all the lines with arrows pointing down are the lines having the negative slope. Negative slope means there is a decrease in the value of y for the increase in the value of x.
From statement 1) lets pick a line having negative slope of -5 say the blue line. Since we have no information about the r that is y intercept it can line on x=-5 line from r = -infinity to + infinity so the line might touch the x axis at infinite locations so this is not sufficient.
Statement 2) given r>o but still there is a lot of space from 0 to infinity so still we cannot have one single value of x - intercept. We also dont know the slope sp there is another infinite combinations of these. so insufficient.
Combining the statements will lead to the Statement 20 ie r>0 and slope m = -5 but since we dont know the value of r exactly there will be infinite values of x intercept....

HOPE U UNDERSTOOD...THANKS.....
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