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

It is currently 18 Apr 2014, 03:10

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

One week a certain vehicle rental outlet had a total of 40

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Director
Director
Joined: 12 Jun 2006
Posts: 539
Followers: 1

Kudos [?]: 7 [0], given: 1

GMAT Tests User
One week a certain vehicle rental outlet had a total of 40 [#permalink] New post 12 Jun 2006, 02:05
One week a certain vehicle rental outlet had a total of 40 cars, 12 trucks, 28 vans and 20 SUVs available. Andre and Barbara went to the vehicle rental outlet and chose 2 vehicles at random, with the condition that Andre and Barbara would not select two of the same type of vehicle (in other words, if one of them has an SUV, the other won't take an SUV, so the second person doesn't even consider the SUVs). What is the probability that, of the two vehicles, one of them is a car of van?

In order to solve, I tried:

40/100*28/60 + 28/100+40/72
This is incorrect.

I was told that I should find the probability of them not choosing a car or van:

20/100*12/80 + 12/100*20/88
This equals 63/1100.
Now, subtract 63/1100 from 1.
Your answer is 1037/1100.

Can anyone explain why I should find the probability of them not choosing a car or van in order to solve. I was told this is the "1-x probability method". Is anyone familiar with this?

Hello by the way.
Manager
Manager
Joined: 01 Jun 2006
Posts: 142
Followers: 1

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

 [#permalink] New post 12 Jun 2006, 03:12
I think that way is not correct. I likely solve the problem this way
The number of ways you can collect 2 car depends on the condition is:
(40*60+12*88+28*72+20*80)=7072
And the ways you collect 2 cars without any car or van is
12*20=240
So the needed probability must be
1-240/7072=427/442
What do u think?
Manager
Manager
Joined: 10 May 2006
Posts: 186
Location: USA
Followers: 1

Kudos [?]: 3 [0], given: 0

GMAT Tests User
Re: Practice Test Question - Please help [#permalink] New post 12 Jun 2006, 14:44
ggarr wrote:
One week a certain vehicle rental outlet had a total of 40 cars, 12 trucks, 28 vans and 20 SUVs available. Andre and Barbara went to the vehicle rental outlet and chose 2 vehicles at random, with the condition that Andre and Barbara would not select two of the same type of vehicle (in other words, if one of them has an SUV, the other won't take an SUV, so the second person doesn't even consider the SUVs). What is the probability that, of the two vehicles, one of them is a car of van?



Prob that A picks a van and B doesn't if A picks first is 28/100 = 7/25. Doesn't matter what B picks.

Prob that A does not pick a van and B does = 72/100 * 28/99 =56/275

Prob that either A or B picks a van = 7/25 + 56/275 = 133/275
VP
VP
User avatar
Joined: 02 Jun 2006
Posts: 1270
Followers: 2

Kudos [?]: 30 [0], given: 0

GMAT Tests User
 [#permalink] New post 12 Jun 2006, 14:51
Is the question "... one of them picks a car or van?"

or

" .. one of them picks a car of type van"?
Director
Director
Joined: 12 Jun 2006
Posts: 539
Followers: 1

Kudos [?]: 7 [0], given: 1

GMAT Tests User
Clarification [#permalink] New post 12 Jun 2006, 15:00
One week a certain vehicle rental outlet had a total of 40 cars, 12 trucks, 28 vans and 20 SUVs available. Andre and Barbara went to the vehicle rental outlet and chose 2 vehicles at random, with the condition that Andre and Barbara would not select two of the same type of vehicle (in other words, if one of them has an SUV, the other won't take an SUV, so the second person doesn't even consider the SUVs). What is the probability that, of the two vehicles, one of them is a car or van?

In order to solve, I tried:

40/100*28/60 + 28/100+40/72
This is incorrect.

I was told that I should find the probability of them not choosing a car or van:

20/100*12/80 + 12/100*20/88
This equals 63/1100.
Now, subtract 63/1100 from 1.
Your answer is 1037/1100.

Can anyone explain why I should find the probability of them not choosing a car or van in order to solve. I was told this is the "1-x probability method". Is anyone familiar with this?

Hello by the way.
Director
Director
Joined: 12 Jun 2006
Posts: 539
Followers: 1

Kudos [?]: 7 [0], given: 1

GMAT Tests User
I don't understand the solution to this, does anyone else? [#permalink] New post 21 Jun 2006, 02:22
Quote:
One week a certain vehicle rental outlet had a total of 40 cars, 12 trucks, 28 vans and 20 SUVs available. Andre and Barbara went to the vehicle rental outlet and chose 2 vehicles at random, with the condition that Andre and Barbara would not select two of the same type of vehicle (in other words, if one of them has an SUV, the other won't take an SUV, so the second person doesn't even consider the SUVs). What is the probability that, of the two vehicles, one of them is a car or van?


According to Manhattan Gmat the correct answer is 1037/1100.
This is arrived at by:

1) finding the prob of them not choosing the car or van
20/100*12/80 + 12/100*20/88.

2) then subtracting the solution, 63/1100, from 1100/1100.

3) Your answer is 1037-1100.

Does anyone have any idea why I need to find the probability of them not choosing a car or van in order to solve? Again, Manhattan Gmat names this method the "1-x probability trick". Has anyone heard of this method?
I don't understand the solution to this, does anyone else?   [#permalink] 21 Jun 2006, 02:22
    Similar topics Author Replies Last post
Similar
Topics:
New posts One week a certain truck rental lot had a total of which lapin 4 30 Aug 2004, 04:31
Popular new posts 20 Experts publish their posts in the topic One week, a certain truck rental lot had a total of 20 cloaked_vessel 15 10 Apr 2005, 12:44
New posts One week a certain truck rental lot had a total of 20 rahulraao 4 03 Sep 2005, 05:09
This topic is locked, you cannot edit posts or make further replies. New One week a certain truck rental lot had a total of 20 trucks mniyer 0 30 Sep 2013, 07:40
New posts 4 Experts publish their posts in the topic One week a certain truck rental lot had a total of 20 trucks Bunuel 5 27 Feb 2014, 06:09
Display posts from previous: Sort by

One week a certain vehicle rental outlet had a total of 40

  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®.