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

Redeem

Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

★★★★★5.0559 reviews
GMATLiveTeach Starts Oct 17
Chris Peckover, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Chris Peckover, 100th-Percentile GMAT Scorer

Oct 17 · Chris Peckover
Sat · 11:00 AM to 2:00 PM ET
Oct 20 · Chris Peckover
Tue, Thu · 8:00 to 10:00 PM ET
Oct 25 · Josh Braslow
Sun · 1:00 to 4:00 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemand 5 seats left Start anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemand Start anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

DS on Co-ordinates

Expert replies
Source: — Data Sufficiency |

by GMATGuruNY » Fri Jan 27, 2012 10:15 am
If lines k and l are perpendicular, they will form four 90 degree angles.
If lines k and l are not perpendicular, they will form two angles less than 90 degrees and two angles greater than 90 degrees.

Question rephrased: Are lines k and l perpendicular?

Many slope questions are best solved by DRAWING.

Statement 1:
Since each line has a positive y-intercept and passes through (3,-2), the two lines cannot be perpendicular:
Image
SUFFICIENT.

Statement 2:
Case 1: Lines k and l are perpendicular, and the two y-intercepts are EQUIDISTANT from (3,-2).
Image
Here, the distance between the y-intercepts = 6.

Case 2: Lines k and l are perpendicular, and the two y-intercepts are NOT EQUIDISTANT from (3,-2).
Image
Here, the distance between the y-intercepts > 6.

Thus, if lines k and l are perpendicular, the MINIMUM distance between the y-intercepts is 6.
Since statement 2 indicates that the distance between the y-intecepts is 5, lines k and l are not perpendicular.
SUFFICIENT.

The correct answer is D.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Join the discussion

by GMATGuruNY » Fri Jan 27, 2012 11:18 am
I received a request for an algebraic approach to statement 2.

Let d = the distance between the y-intercepts of two perpendicular lines that intersect to the right of the y-axis.
Let's assume that neither line has an undefined slope.
Let the equation of the line with the greater y-intercept be y = mx+b.
Then the equation of the line with the smaller y-intercept is y = (-1/m)x + (b-d).

At the point of intersection, the two lines have the same y value:
mx + b = (-1/m)x + (b-d)
mx = (-1/m)x - d
x(m²) = -x - dm
x(m²) + dm + x = 0.

The discriminant of ax² + bx + c = 0 is b²-4ac.
Thus, the discriminant of x(m²) + dm + x = 0 is:
d²-4(x)(x) = d² - 4x².

For a quadratic to have a real solution, its discriminant must be greater than or equal to 0:
d² - 4x² ≥ 0
d² ≥ 4x²
d²/x² ≥ 4
d/x ≥ 2.

In the inequality above:
d is the distance between the y-intercepts.
x is the distance between the y-axis and the point of intersection.
The value of d is at least two times the value of x.

Thus, the distance between the y-intercepts is AT LEAST TWICE the distance between the y-axis and the point of intersection.
This will be true of any two perpendicular lines with defined slopes.

In statement 2, the distance between the y-intercepts (5) is less than twice the distance between the y-axis and (3,-2).
Thus, lines k and l are not perpendicular.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Join the discussion

by Prashant Ranjan » Sun Jan 29, 2012 4:03 am
Pardon Mitch for asking me this.
But if we assume the distance between the two y intercepts of the perpendicular lines to be d and y intercept of one line to be 'b', then shouldn't the y intercept of the other line be 'd-b'?

Thanks
Join the discussion

by GMATGuruNY » Sun Jan 29, 2012 5:03 am
Prashant Ranjan wrote:Pardon Mitch for asking me this.
But if we assume the distance between the two y intercepts of the perpendicular lines to be d and y intercept of one line to be 'b', then shouldn't the y intercept of the other line be 'd-b'?

Thanks
My explanation indicates that the equation of the line with the GREATER y-intercept is y = mx + b.
Since the other line has a LOWER y-intercept -- and the positive distance between the y-intercepts is d -- the y-intercept of the other line is b-d.
To illustrate:
If the higher y-intercept is b=10, and the distance between the y-intercepts is d=2, the lower y-intercept = b-d = 10-2 = 8.
(Using your logic, the lower y-intercept would be d-b = 2-10 = -8. Here, the distance between the y-intercepts = 10-(-8) = 18, which is not the value of d.)
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Join the discussion