GMAT PREP question

BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

This topic has expert replies

Post new topic Post Reply

Previous Topic Next Topic

priyankamishra11: Master | Next Rank: 500 Posts; Posts: 120; Joined: Thu May 15, 2008 1:07 pm; Location: Boston .US; Thanked: 1 times

GMAT PREP question

by priyankamishra11 » Thu Aug 14, 2008 9:48 am

Please explain why 2nd stmt. is not sufficient?

Attachments

Doc2.doc: (218.5 KiB) Downloaded 118 times

Regards,
Priyanka

Quote

Source: Beat The GMAT — Data Sufficiency | Thu Aug 14, 2008 9:48 am

Stuart@KaplanGMAT: GMAT Instructor; Posts: 3225; Joined: Tue Jan 08, 2008 2:40 pm; Location: Toronto; Thanked: 1710 times; Followed by:614 members; GMAT Score:800

Re: GMAT PREP question

by Stuart@KaplanGMAT » Thu Aug 14, 2008 9:55 am

priyankamishra11 wrote:Please explain why 2nd stmt. is not sufficient?

(2) the y intercept of k is -6

Well, if the equation of line k is y=-6, then k will not intersect sector II.

If the equation of line k is y = -(1/6)x - 6, then k will intersect sector II.

So, the answer could be "no" or "yes": insufficient.

Here's the general rule on which you're being tested:

A line with a negative slope will ALWAYS intersect sectors II and IV. (It will also pass through one of the other sectors, unless it passes through the origin.)

A line with a positive slope will ALWAYS intersect sectors I and III. (It will also pass through one of the other sectors, unless it passes through the origin.)

Stuart Kovinsky | Kaplan GMAT Faculty | Toronto

Kaplan Exclusive: The Official Test Day Experience | Ready to Take a Free Practice Test? | Kaplan/Beat the GMAT Member Discount
BTG100 for $100 off a full course

Quote

anju: Master | Next Rank: 500 Posts; Posts: 258; Joined: Thu Mar 29, 2007 3:15 am; Thanked: 7 times; Followed by:1 members

Re: GMAT PREP question

by anju » Thu Aug 14, 2008 12:25 pm

Stuart Kovinsky wrote:
priyankamishra11 wrote:Please explain why 2nd stmt. is not sufficient?
(2) the y intercept of k is -6

Well, if the equation of line k is y=-6, then k will not intersect sector II.

If the equation of line k is y = -(1/6)x - 6, then k will intersect sector II.

So, the answer could be "no" or "yes": insufficient.

Here's the general rule on which you're being tested:

A line with a negative slope will ALWAYS intersect sectors II and IV. (It will also pass through one of the other sectors, unless it passes through the origin.)

A line with a positive slope will ALWAYS intersect sectors I and III. (It will also pass through one of the other sectors, unless it passes through the origin.)

Hi Stuart,

Can you pls. elaborate :
If the equation of line k is y = -(1/6)x - 6, then k will intersect sector II.
So, the answer could be "no" or "yes": insufficient.
How did u get this equaltion from statement 2 alone?

Thanks

Quote

Stuart@KaplanGMAT: GMAT Instructor; Posts: 3225; Joined: Tue Jan 08, 2008 2:40 pm; Location: Toronto; Thanked: 1710 times; Followed by:614 members; GMAT Score:800

Re: GMAT PREP question

by Stuart@KaplanGMAT » Thu Aug 14, 2008 1:19 pm

anju wrote:
Stuart Kovinsky wrote:
priyankamishra11 wrote:Please explain why 2nd stmt. is not sufficient?
(2) the y intercept of k is -6

Well, if the equation of line k is y=-6, then k will not intersect sector II.

If the equation of line k is y = -(1/6)x - 6, then k will intersect sector II.

So, the answer could be "no" or "yes": insufficient.

Here's the general rule on which you're being tested:

A line with a negative slope will ALWAYS intersect sectors II and IV. (It will also pass through one of the other sectors, unless it passes through the origin.)

A line with a positive slope will ALWAYS intersect sectors I and III. (It will also pass through one of the other sectors, unless it passes through the origin.)
Hi Stuart,

Can you pls. elaborate :
If the equation of line k is y = -(1/6)x - 6, then k will intersect sector II.
So, the answer could be "no" or "yes": insufficient.
How did u get this equaltion from statement 2 alone?

Thanks

All we know from statement (2) is that the y intercept is -6.

When we pick numbers in data sufficient yes/no questions, our goal is to get both a "yes" answer AND a "no" answer. So, I just picked a line (that satisfied the condition in the rule, i.e. y-int of -6) with a slope that would generate a "yes" answer.