It is currently 17 Oct 2017, 21:21

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.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

If the probability of observing a car in 30 minutes on a

  post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Senior Manager
Senior Manager
avatar
Joined: 19 Apr 2008
Posts: 315

Kudos [?]: 99 [0], given: 0

If the probability of observing a car in 30 minutes on a [#permalink]

Show Tags

New post 14 Sep 2008, 15:51
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

If the probability of observing a car in 30 minutes on a highway is 0.95, what is the probability of observing a car in 10 minutes (assuming constant default probability)?

Kudos [?]: 99 [0], given: 0

VP
VP
User avatar
Joined: 05 Jul 2008
Posts: 1402

Kudos [?]: 437 [0], given: 1

Re: interesting probability question [#permalink]

Show Tags

New post 14 Sep 2008, 15:59
rpmodi wrote:
If the probability of observing a car in 30 minutes on a highway is 0.95, what is the probability of observing a car in 10 minutes (assuming constant default probability)?


I would say 1/3rd of 0.95

But who knows, This Q is pretty uncommon

Kudos [?]: 437 [0], given: 1

Intern
Intern
avatar
Joined: 03 Sep 2008
Posts: 22

Kudos [?]: 10 [0], given: 0

Re: interesting probability question [#permalink]

Show Tags

New post 14 Sep 2008, 16:29
You can't do this type of problem without knowing something about the probability distribution. Is it uniform, exponential, normal? This involves a continuous probability distribution and the GMAT deals primarily with discrete distributions.

Kudos [?]: 10 [0], given: 0

Senior Manager
Senior Manager
avatar
Joined: 19 Apr 2008
Posts: 315

Kudos [?]: 99 [0], given: 0

Re: interesting probability question [#permalink]

Show Tags

New post 14 Sep 2008, 21:50
it says constant default probability , so that's the hint ...i don't know if this will be a GMAT problem but sure is an interesting question ...

Kudos [?]: 99 [0], given: 0

SVP
SVP
avatar
Joined: 17 Jun 2008
Posts: 1535

Kudos [?]: 279 [0], given: 0

Re: interesting probability question [#permalink]

Show Tags

New post 14 Sep 2008, 22:50
Not sure what the meaning of "default probability" is in "constant default probability". I give up. However, if asked in the exam, I will guess 1/3rd of 0.95.

Kudos [?]: 279 [0], given: 0

Manager
Manager
avatar
Joined: 22 Jul 2008
Posts: 147

Kudos [?]: 18 [0], given: 0

Re: interesting probability question [#permalink]

Show Tags

New post 15 Sep 2008, 16:02
Let prob. of seeing a car in 10 mins. be = p
Therefore, the prob. of not seeing the car is 1-p
Total 30 mins. prob = prob. at 10 mins + prob. at 20 mins + prob at 30 mins.
= p + (1-p)*p + (1-p)*(1-p)*p = 0.95
p[1 + (1-p) + (1-p)*2] = 0.95
This is a GP
p* [(1-p)^3-1]/(p-1) = 0.95
p^3 -3p^2 + 3p = 0.95
Hence p can be calculated from this cubic equation.

Kudos [?]: 18 [0], given: 0

Re: interesting probability question   [#permalink] 15 Sep 2008, 16:02
Display posts from previous: Sort by

If the probability of observing a car in 30 minutes on a

  post reply Question banks Downloads My Bookmarks Reviews Important topics  


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

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

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®.