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

It is currently 25 Aug 2016, 17:51
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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

A certain businessman wears only three different colors of shirt -- wh

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

Hide Tags

Manager
Manager
User avatar
Status: Still Struggling
Joined: 03 Nov 2010
Posts: 138
Location: India
GMAT Date: 10-15-2011
GPA: 3.71
WE: Information Technology (Computer Software)
Followers: 5

Kudos [?]: 66 [0], given: 8

A certain businessman wears only three different colors of shirt -- wh [#permalink]

Show Tags

New post 16 Dec 2010, 01:32
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

63% (02:01) correct 38% (01:12) wrong based on 8 sessions

HideShow timer Statistics

A certain businessman wears only three different colors of shirt -- white, blue, and gray. The probability that he will wear a blue or gray shirt is 2/3. During a four-day work week, what is the probability that the businessman will wear a white shirt at least once?


OA:
[Reveal] Spoiler:
65/81

_________________

Appreciation in KUDOS please!
Knewton Free Test 10/03 - 710 (49/37)
Princeton Free Test 10/08 - 610 (44/31)
Kaplan Test 1- 10/10 - 630
Veritas Prep- 10/11 - 630 (42/37)
MGMAT 1 - 10/12 - 680 (45/34)

1 KUDOS received
Kaplan GMAT Instructor
User avatar
Joined: 21 Jun 2010
Posts: 148
Location: Toronto
Followers: 44

Kudos [?]: 173 [1] , given: 0

Re: A certain businessman wears only three different colors of shirt -- wh [#permalink]

Show Tags

New post 16 Dec 2010, 02:45
1
This post received
KUDOS
krishnasty wrote:
A certain businessman wears only three different colors of shirt -- white, blue, and gray. The probability that he will wear a blue or gray shirt is 2/3. During a four-day work week, what is the probability that the businessman will wear a white shirt at least once?


OA: 65/18


Hi!

There's a typo with the OA - you've got the digits in the denominator reversed.

So, let's ignore the "OA" and solve.

For complex probability questions, it's almost always quicker to solve with the "one minus" approach:

Probability (what you want) = 1 - Probability (what you don't want)

Here we want white on at least one day. So, we don't want no white shirts at all.

Since the probability of blue or grey is 2/3,

the probability of no white on any of the 4 days = (2/3)(2/3)(2/3)(2/3) = 16/81

1 - 16/81 = 65/81... done!
Manager
Manager
User avatar
Status: Still Struggling
Joined: 03 Nov 2010
Posts: 138
Location: India
GMAT Date: 10-15-2011
GPA: 3.71
WE: Information Technology (Computer Software)
Followers: 5

Kudos [?]: 66 [0], given: 8

Re: A certain businessman wears only three different colors of shirt -- wh [#permalink]

Show Tags

New post 16 Dec 2010, 04:13
sorry for the typo...the OA was indeed 65/81..

Kudos to u.!!
_________________

Appreciation in KUDOS please!
Knewton Free Test 10/03 - 710 (49/37)
Princeton Free Test 10/08 - 610 (44/31)
Kaplan Test 1- 10/10 - 630
Veritas Prep- 10/11 - 630 (42/37)
MGMAT 1 - 10/12 - 680 (45/34)

Senior Manager
Senior Manager
User avatar
Status: Bring the Rain
Joined: 17 Aug 2010
Posts: 406
Location: United States (MD)
Concentration: Strategy, Marketing
Schools: Michigan (Ross) - Class of 2014
GMAT 1: 730 Q49 V39
GPA: 3.13
WE: Corporate Finance (Aerospace and Defense)
Followers: 7

Kudos [?]: 43 [0], given: 46

Re: A certain businessman wears only three different colors of shirt -- wh [#permalink]

Show Tags

New post 16 Dec 2010, 07:25
This is what I did

1-(Prob of 4 days non white)=1-(2/3)(2/3)(2/3)(2/3)=1-(16/81)=65/81
_________________

Go Blue!

GMAT Club Premium Membership - big benefits and savings

Re: A certain businessman wears only three different colors of shirt -- wh   [#permalink] 16 Dec 2010, 07:25
    Similar topics Author Replies Last post
Similar
Topics:
1 Experts publish their posts in the topic People standing in a straight line are wearing alternating colored shi Bunuel 1 25 Apr 2016, 04:07
1 Experts publish their posts in the topic A woman has three blouses of different colors, three skirts of differe Bunuel 1 17 Jan 2016, 12:10
14 Experts publish their posts in the topic A certain ski shop sells pairs of gloves in 12 different colors aadikamagic 10 08 Oct 2014, 20:57
11 Experts publish their posts in the topic A certain calculating machine has only three operation butto anon1 12 19 Nov 2012, 17:41
33 Experts publish their posts in the topic Five balls of different colors are to be placed in three avaneeshvyas 30 18 Oct 2012, 14:12
Display posts from previous: Sort by

A certain businessman wears only three different colors of shirt -- wh

  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®.