Find all School-related info fast with the new School-Specific MBA Forum

It is currently 30 Jul 2015, 13:16
GMAT Club Tests

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Set T consists of all points (x, y) such that x^2 + y^2 = 1.

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Current Student
User avatar
Joined: 11 May 2008
Posts: 560
Followers: 7

Kudos [?]: 64 [0], given: 0

Set T consists of all points (x, y) such that x^2 + y^2 = 1. [#permalink] New post 26 Aug 2008, 11:26
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Set T consists of all points (x, y) such that x^2 + y^2 = 1. If point (a, b) is selected from set T at random, what is the probability that b> a + 1 ?



1/4
1/3
1/2
3/5
2/3

ZIS A CLUB PROBLEM!! SO CHEERS!! HIC :lol: :drunk
Director
Director
User avatar
Joined: 12 Jul 2008
Posts: 518
Schools: Wharton
Followers: 17

Kudos [?]: 124 [0], given: 0

Re: GEOMETRIC PROB [#permalink] New post 26 Aug 2008, 11:38
arjtryarjtry wrote:
Set T consists of all points (x, y) such that x^2 + y^2 = 1. If point (a, b) is selected from set T at random, what is the probability that b> a + 1 ?

1/4
1/3
1/2
3/5
2/3


1/4

x^2 + y^2 = 1 describes a circle with radius 1 centered at (0,0).

Split the circle into fourths using the coordinate plane's quadrants

Quadrant 1:
a and b are positive
Here, b < a + 1

Quadrant 2:
a is negative and b is positive
Here b > a + 1

Quadrant 3:
a is negative and b is negative
Here b < a+1

Quadrant 4:
a is positive and b is negative
Here b < a + 1
SVP
SVP
User avatar
Joined: 07 Nov 2007
Posts: 1824
Location: New York
Followers: 29

Kudos [?]: 572 [0], given: 5

Re: GEOMETRIC PROB [#permalink] New post 26 Aug 2008, 22:05
arjtryarjtry wrote:
Set T consists of all points (x, y) such that x^2 + y^2 = 1. If point (a, b) is selected from set T at random, what is the probability that b> a + 1 ?



1/4
1/3
1/2
3/5
2/3

ZIS A CLUB PROBLEM!! SO CHEERS!! HIC :lol: :drunk


I got 1/4 too..

I drew the CIRCLE with (0,0) as centre .

y=x+1 -- line cuts the circle in II quadrant (1/4 of the circle)
y>x+1 (b>a+1) --> consitute 1/4 of all points.


what is OA.
_________________

Your attitude determines your altitude
Smiling wins more friends than frowning

Director
Director
User avatar
Joined: 03 Sep 2006
Posts: 884
Followers: 6

Kudos [?]: 307 [0], given: 33

GMAT ToolKit User
Re: GEOMETRIC PROB [#permalink] New post 26 Aug 2008, 22:50
x^2 + y^2 = 1 is the equation of a circle with radius "1".

Probability of the following linear equation to hold true;

y > x+1

See the attached file;

shouldn't the answer be = 1/11??
Attachments

Probability2.PNG
Probability2.PNG [ 22.72 KiB | Viewed 751 times ]

Current Student
User avatar
Joined: 11 May 2008
Posts: 560
Followers: 7

Kudos [?]: 64 [0], given: 0

Re: GEOMETRIC PROB [#permalink] New post 27 Aug 2008, 00:07
yes... even i got a diagram similar to the one above...
so how is the ans 1/4?
when the area above the line is not 1/4 of area of the circle?
Manager
Manager
avatar
Joined: 14 Jun 2008
Posts: 161
Followers: 1

Kudos [?]: 28 [0], given: 0

Re: GEOMETRIC PROB [#permalink] New post 27 Aug 2008, 00:16
because we are concerned with only point that are ON the circle, not inside
thereofre only that lie on the black

the points in that quadrant are 1/4 of the total circle
Intern
Intern
avatar
Joined: 23 Feb 2006
Posts: 5
Followers: 0

Kudos [?]: 0 [0], given: 0

Re: GEOMETRIC PROB [#permalink] New post 27 Aug 2008, 00:51
sset009 wrote:
because we are concerned with only point that are ON the circle, not inside
thereofre only that lie on the black

the points in that quadrant are 1/4 of the total circle


Agree. Remember Set T refers to all points that are on the circumference of the circle and not inside.
Re: GEOMETRIC PROB   [#permalink] 27 Aug 2008, 00:51
Display posts from previous: Sort by

Set T consists of all points (x, y) such that x^2 + y^2 = 1.

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.