When a random experiment is conducted, the probability that : GMAT Problem Solving (PS)
Check GMAT Club App Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

It is currently 09 Dec 2016, 07:39
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.

Close

Request Expert Reply

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

When a random experiment is conducted, the probability that

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

Hide Tags

Manager
Manager
User avatar
Status: Its Wow or Never
Joined: 11 Dec 2009
Posts: 205
Location: India
Concentration: Technology, Strategy
GMAT 1: 670 Q47 V35
GMAT 2: 710 Q48 V40
WE: Information Technology (Computer Software)
Followers: 11

Kudos [?]: 184 [0], given: 7

When a random experiment is conducted, the probability that [#permalink]

Show Tags

New post 29 Jan 2010, 10:26
6
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

77% (02:16) correct 23% (01:56) wrong based on 108 sessions

HideShow timer Statistics

When a random experiment is conducted, the probability that event A occurs is 1/3. If the random experiment is conducted 5 independent times, what is the probability that event A occurs exactly twice?

A. 5/243
B. 25/243
C. 64/243
D. 80/243
E. 16/17
[Reveal] Spoiler: OA

_________________

---------------------------------------------------------------------------------------
If you think you can,you can
If you think you can't,you are right.


Last edited by Bunuel on 08 Jun 2012, 05:49, edited 2 times in total.
Edited the question and added the OA
Expert Post
CEO
CEO
User avatar
Joined: 17 Nov 2007
Posts: 3589
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 531

Kudos [?]: 3457 [0], given: 360

Re: Probability [#permalink]

Show Tags

New post 29 Jan 2010, 10:34
mojorising800 wrote:
When a random experiment is conducted, the probability that event A occurs is ????. If the random experiment is conducted 5 independent times, what is the probability that event A occurs exactly twice?

You need to add information about the probability that even A occurs
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Intern
Intern
avatar
Joined: 31 Dec 2009
Posts: 13
Followers: 0

Kudos [?]: 4 [0], given: 5

Re: Probability [#permalink]

Show Tags

New post 29 Jan 2010, 19:42
What am I missing here? :roll:

Lets say getting A is represented by W and not getting A by L.
prob of A = 3/10
prob of not getting A= 7/10
Out of 5 times, getting 2 As can be done in 5C2 = 10 ways.

So prob of getting 2 As = 10*3/10 * 3/10 * 7/10 * 7/10 * 7/10 = 3087 / 10000
1 KUDOS received
Manager
Manager
avatar
Joined: 27 May 2012
Posts: 216
Followers: 2

Kudos [?]: 67 [1] , given: 431

Re: Probability [#permalink]

Show Tags

New post 08 Jun 2012, 05:41
1
This post received
KUDOS
I think this should be

[.3 * .3 * .7 * .7 * .7 ] * 5!/ 3! 2!=

.03087 * 10 = .3087 how ever this does not match any given options
_________________

- Stne

Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 35932
Followers: 6858

Kudos [?]: 90081 [0], given: 10413

Re: Probability [#permalink]

Show Tags

New post 08 Jun 2012, 05:50
stne wrote:
I think this should be

[.3 * .3 * .7 * .7 * .7 ] * 5!/ 3! 2!=

.03087 * 10 = .3087 how ever this does not match any given options


You are right. There was a typo in the stem, 0.3 instead of 1/3. Typo edited. Thank you.

Complete solution:
When a random experiment is conducted, the probability that event A occurs is 1/3. If the random experiment is conducted 5 independent times, what is the probability that event A occurs exactly twice?
A. 5/243
B. 25/243
C. 64/243
D. 80/243
E. 16/17

The probability that event A occurs is \(\frac{1}{3}\);
The probability that event A will not occur is \(1-\frac{1}{3}=\frac{2}{3}\).

We want to calculate the probability of event YYNNN (Y-occurs, N-does not occur).

\(P(YYNNN)=\frac{5!}{2!3!}*(\frac{1}{3})^2*(\frac{2}{3})^3=\frac{80}{243}\), we are multiplying by \(\frac{5!}{2!3!}\) as event YYNNN can happen in # of times: YYNNN, YNYNN, NNNYY, ... basically the # of permutations of 5 letters YYNNN out of which 2 Y's and 3 N's are identical (\(\frac{5!}{2!3!}\)).

Answer: D.

Hope it's clear.
_________________

New to the Math Forum?
Please read this: All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

1 KUDOS received
Director
Director
User avatar
Joined: 23 Jan 2013
Posts: 568
Schools: Cambridge'16
Followers: 1

Kudos [?]: 41 [1] , given: 40

CAT Tests
When a random experiment is conducted, the probability that [#permalink]

Show Tags

New post 05 Oct 2014, 03:09
1
This post received
KUDOS
one case is:
1/3*1/3*2/3*2/3*2/3=2^3/3^5

we have 5!/2!*3!=10 such cases

so, 2^3*10/3^5=80/243


D
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 12903
Followers: 562

Kudos [?]: 158 [0], given: 0

Premium Member
Re: When a random experiment is conducted, the probability that [#permalink]

Show Tags

New post 18 Feb 2016, 22:47
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 Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Re: When a random experiment is conducted, the probability that   [#permalink] 18 Feb 2016, 22:47
    Similar topics Author Replies Last post
Similar
Topics:
10 Experts publish their posts in the topic Wes works at a science lab that conducts experiments on bacteria. The Bunuel 3 06 Oct 2014, 08:17
11 Experts publish their posts in the topic In a certain random experiment, exactly one of the outcomes goodyear2013 3 12 Jan 2014, 15:44
14 Experts publish their posts in the topic Find the probability that a leap year selected at random antoxavier 3 30 Jan 2013, 22:30
1 What is the probability that a random arrangement of the letters IIITT Sepideh2612 4 08 Nov 2011, 00:39
11 Experts publish their posts in the topic When a random experiment is conducted, the probability that hemanthp 8 26 Sep 2010, 08:38
Display posts from previous: Sort by

When a random experiment is conducted, the probability that

  new topic 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 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®.