GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 23 Apr 2019, 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.

Close

Request Expert Reply

Confirm Cancel

The probability of a man hitting a bulls eye in one fire is

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

 
Senior Manager
Senior Manager
avatar
Joined: 15 Jun 2010
Posts: 292
Schools: IE'14, ISB'14, Kellogg'15
WE 1: 7 Yrs in Automobile (Commercial Vehicle industry)
Reviews Badge
The probability of a man hitting a bulls eye in one fire is  [#permalink]

Show Tags

New post Updated on: 07 Aug 2012, 07:10
4
7
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

70% (01:52) correct 30% (02:20) wrong based on 241 sessions

HideShow timer Statistics

The probability of a man hitting a bulls eye in one fire is 1/4. What is the least number of times that the man should fire in order to take the probability of hitting the bulls eye at least once to more than 50%.

A. 5
B. 7
C. 3
D. 12
E. 6

_________________
Regards
SD
-----------------------------
Press Kudos if you like my post.
Debrief 610-540-580-710(Long Journey): http://gmatclub.com/forum/from-600-540-580-710-finally-achieved-in-4th-attempt-142456.html

Originally posted by SOURH7WK on 07 Aug 2012, 06:49.
Last edited by SOURH7WK on 07 Aug 2012, 07:10, edited 2 times in total.
Most Helpful Community Reply
Manager
Manager
avatar
Joined: 05 Jul 2012
Posts: 60
Location: India
Concentration: Finance, Strategy
GMAT Date: 09-30-2012
GPA: 3.08
WE: Engineering (Energy and Utilities)
Re: The probability of a man hitting a bulls eye in one fire is  [#permalink]

Show Tags

New post 07 Aug 2012, 09:13
4
4
SOURH7WK wrote:
The probability of a man hitting a bulls eye in one fire is 1/4. What is the least number of times that the man should fire in order to take the probability of hitting the bulls eye at least once to more than 50%.

A. 5
B. 7
C. 3
D. 12
E. 6


It is a Typical Probability Question
IN Probability we have a rule ( which is logic actually) that
P(>1) = 1-P(0)
That is Probability of hitting the bulls eye at least once out of N trials is 1- probability of missing it all the times. & P of missing it is 3/4

That means\(1-(\frac{3}{4})^n\) > \(\frac{1}{2}\)

Solve it , n > 3 satisfies.
General Discussion
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 54462
Re: The probability of a man hitting a bulls eye in one fire is  [#permalink]

Show Tags

New post 07 Aug 2012, 07:05
3
SOURH7WK wrote:
The probability of a man hitting a bulls eye in one fire is 1/4. What is the least number of times that the man should fire in order to take the probability of hitting the bulls eye at least once to more than 50%.

A. 5
B. 7
C. 3
D. 12
E. 6

OA will follow after few discussions


The probability that the man hits the bulls eye at least once in 2 tries is 1-(3/4)^2=7/16, so less than 1/2 (the probability of hitting the bulls eye at least once is 1 minus the probability of the opposite event, so the probability that the men misses in all 2 tries).

The probability that the man hits the bulls eye at least once in 3 tries is 1-(3/4)^3=37/64, so more than 1/2.

Answer: C.

P.S. You must indicate OA, rule #7: rules-for-posting-please-read-this-before-posting-133935.html
_________________
Manager
Manager
avatar
Joined: 23 Jan 2011
Posts: 112
Re: The probability of a man hitting a bulls eye in one fire is  [#permalink]

Show Tags

New post 08 Aug 2012, 10:20
very helpful Bunuel/mandyr, need to revise the "at least" rule and this helps, thank you both
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 54462
Re: The probability of a man hitting a bulls eye in one fire is  [#permalink]

Show Tags

New post 14 Jul 2013, 00:10
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 10602
Re: The probability of a man hitting a bulls eye in one fire is  [#permalink]

Show Tags

New post 01 Aug 2017, 19:08
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Club Bot
Re: The probability of a man hitting a bulls eye in one fire is   [#permalink] 01 Aug 2017, 19:08
Display posts from previous: Sort by

The probability of a man hitting a bulls eye in one fire is

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| 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®.