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
Vote for Target Test Prep, Newsweek Readers’ Choice Awards 2026
NEWSWEEK READERS’ CHOICE 2026

BIG NEWS! Target Test Prep has been nominated, and they’d love your vote!

TTP has worked incredibly hard to build the best test prep experience possible, and winning Newsweek’s 2026 Readers’ Choice Award for Best Test Prep would mean a lot to them. If TTP has helped you, they’d be incredibly grateful for your vote. You can vote once each day through September 9.

Vote for TTP
GMATLiveTeach 7 seats left
Chris Peckover
NEXT LIVE COHORT

Oct 13 to Jan 7, 2027

with Chris Peckover

Schedule
Tue, Thu · 8:00 to 10:00 PM ET
Included
40 live hours + 6 months of GMAT OnDemand
  • Live instruction and real-time questions
  • Class recordings and assigned practice
View class & enroll
Limited cohort · enrollment openTarget Test Prep
EALiveTeach 5 seats left
Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

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
Limited cohort · enrollment openTarget 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.

Lines and planes

Expert replies
by winnerhere » Thu Oct 14, 2010 5:45 pm
Twelve straight lines are drawn i a plane such that no two of them are parallel and no three of them are concurrent. A circle is now drawn in the same plane such that all points of intersection of all the lines lie inside the circle.What is the number of non overlapping regions into which the circle is divided?


1) 25

2) 69

3) 79

4) 83

5)60
Last edited by winnerhere on Sun Oct 17, 2010 7:55 am, edited 1 time in total.
Join the discussion
Source: — Problem Solving |

by GMATGuruNY » Thu Oct 14, 2010 7:35 pm
winnerhere wrote:Twelve straight lines are drawn i a plane such that no two of them are parallel and no three of them are concurrent. A circle is now drawn in the same plane such that all points of intersection of all the lines lie inside the circle.What is the number of non overlapping regions into which the circle is divided?


1) 25

2) 69

3) 75

4) 83

5)60
The question seems to be asking for the maximum number of non-overlapping regions that can be formed by 12 lines intersecting inside a circle. Here's the rule:

The nth line drawn will add n more regions to the circle.

1st line adds 1 region to the circle for a total of 2 regions.
2nd line adds 2 more regions to the circle, bringing the total number of regions to 2+2=4.
3nd line adds 3 more regions to the circle, bringing the total number of regions to 4+3=7.
4th line adds 4 more regions to the circle, bringing the total number of regions to 7+4=11.
5th line adds 5 more regions to the circle, bringing the total number of regions to 11+5=16.
6th line adds 6 more regions to the circle, bringing the total number of regions to 16+6=22.
7th line adds 7 more regions to the circle, bringing the total number of regions to 22+7=29.
8th line adds 8 more regions to the circle, bringing the total number of regions to 29+8=37.
9th line adds 9 more regions to the circle, bringing the total number of regions to 37+9=46.
10th line adds 10 more regions to the circle, bringing the total number of regions to 46+10=56.
11th line adds 11 more regions to the circle, bringing the total number of regions to 56+11=67.
12th line adds 12 more regions to the circle, bringing the total number of regions to 67+12=79.

The correct answer should be 79. Are you certain that the answer choices have been transcribed correctly?
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 winnerhere » Sun Oct 17, 2010 7:50 am
-edited-
Last edited by winnerhere on Sun Oct 17, 2010 7:58 am, edited 1 time in total.
Join the discussion

by winnerhere » Sun Oct 17, 2010 7:58 am
@gmatguru..yes the answer is 79 ..great ..thanks for the logic that you have provided.
Join the discussion