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

It is currently 21 Oct 2014, 13:30

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

1) there is a square in the XY co-ordinate system with its

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Senior Manager
Senior Manager
avatar
Joined: 21 Aug 2003
Posts: 258
Location: Bangalore
Followers: 1

Kudos [?]: 4 [0], given: 0

1) there is a square in the XY co-ordinate system with its [#permalink] New post 25 Sep 2003, 06:58
1) there is a square in the XY co-ordinate system with its vertices
as {(1,1), (1,-1), (-1,-1), (-1,1)}. What is the probability that a
point picked at random within this square region will satisfy the
equation x^2+y^2<1?

2) if 2 numbers are chosen from 0-9 inclusive, what is the
probability that its product will be even?
SVP
SVP
User avatar
Joined: 03 Feb 2003
Posts: 1613
Followers: 6

Kudos [?]: 53 [0], given: 0

 [#permalink] New post 25 Sep 2003, 08:04
(1) X^2+Y^2<1 is an origin-center circle, its radius being 1.

So, employ the geometrical sense of the probability: the favorable area/the total area

FA=pi
TA=4

P=pi/4

(2) P(an even product of the two)=1-P(odd,odd)=1-[5/10*4/9]=1-2/9=7/9
Manager
Manager
avatar
Joined: 15 Sep 2003
Posts: 74
Location: california
Followers: 1

Kudos [?]: 1 [0], given: 0

 [#permalink] New post 25 Sep 2003, 08:51
i agree with stolyar
Intern
Intern
avatar
Joined: 11 Jul 2003
Posts: 28
Followers: 0

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

 [#permalink] New post 25 Sep 2003, 12:05
1. Please can u explain how the equation is the origin of a circle. I do not understand.

2. I do not understand why 1-p(O,O) is used, as we need to select only one even number, the second number can be either odd or even, as we nedd the product ot be even.

so P(even #)=5/10 * P(any other #)9/9 = 0.5

am i right ?
SVP
SVP
User avatar
Joined: 03 Feb 2003
Posts: 1613
Followers: 6

Kudos [?]: 53 [0], given: 0

 [#permalink] New post 25 Sep 2003, 21:07
(1) the equation of an origin-centered circumference is x^2+y^2=R^2, a direct use of the Pythagorean theorem.

(2) all the possible combinations for a product are EE, EO, OE, OO. The first three gives an even product; the last one gives an odd one. So, it is correct to calculate probabilities for each of the first three cases and add them up, but it is more concise and elegant to calculate the probability of the opposite case and subtract it from 1.
Intern
Intern
User avatar
Joined: 24 Sep 2003
Posts: 38
Location: India
Followers: 1

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

 [#permalink] New post 25 Sep 2003, 21:49
1. Because there is no term having x and y in the equation of circle. A general equation of circle is (X-x)**2 + (Y-y)**2=R**2. That's why it's circle having centre as origin and radius is 1.


2. There should be atleast one number should be even out of 2, if there multiplication is even. So if deduct probability of multiplication of (odd,odd) from total probability (i.e. 1), we can get desired probability.
Senior Manager
Senior Manager
avatar
Joined: 21 Aug 2003
Posts: 258
Location: Bangalore
Followers: 1

Kudos [?]: 4 [0], given: 0

 [#permalink] New post 26 Sep 2003, 09:30
stolyar's answers are correct.. good.
-vicky
Intern
Intern
avatar
Joined: 11 Jul 2003
Posts: 28
Followers: 0

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

THANKS [#permalink] New post 26 Sep 2003, 12:20
Thanks for the explanations.
THANKS   [#permalink] 26 Sep 2003, 12:20
    Similar topics Author Replies Last post
Similar
Topics:
xy-coordinate system, points (2, 9) and (-1, 0) nitya34 1 03 Sep 2009, 23:44
In the xy-coordinate system, what is the slope of the line iamba 9 01 Jul 2007, 10:33
11 In the xy-coordinate system, what is the slope of the line ArvGMAT 11 16 Jun 2007, 19:01
In the xy-coordinate system, rectangle ABCD is inscribed kuristar 1 04 May 2006, 08:06
In the xy-coordinate system, rectangle ABCD is inscribed ywilfred 4 23 Mar 2005, 23:37
Display posts from previous: Sort by

1) there is a square in the XY co-ordinate system with its

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

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®.