Last visit was: 27 Apr 2026, 04:41 It is currently 27 Apr 2026, 04:41
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
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 27 Apr 2026
Posts: 109,928
Own Kudos:
811,525
 [3]
Given Kudos: 105,914
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,928
Kudos: 811,525
 [3]
1
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
avatar
Sushmitha123
Joined: 05 Jul 2017
Last visit: 20 Oct 2017
Posts: 2
Own Kudos:
Given Kudos: 2
Posts: 2
Kudos: 1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
pushpitkc
Joined: 26 Feb 2016
Last visit: 19 Feb 2025
Posts: 2,800
Own Kudos:
6,236
 [2]
Given Kudos: 47
Location: India
GPA: 3.12
Posts: 2,800
Kudos: 6,236
 [2]
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
User avatar
prerakgoel03
Joined: 05 Feb 2017
Last visit: 30 Apr 2021
Posts: 25
Own Kudos:
Given Kudos: 50
Posts: 25
Kudos: 27
Kudos
Add Kudos
Bookmarks
Bookmark this Post
The answer is D.

2/3 :- Probability of wearing the blue or grey shirt
1/3:- Probability of wearing the white shirt


1 Day = 4C1*(1/3)*(2/3)^3=32/81
2 Days = 4C2*(1/3)^2*(2/3)^2=24/81
3 Days = 4C3*(1/3)^3*(2/3)^1=8/81
4 Days = 4C4*(1/3)^4 =1/81

On Adding we get 65/81 . D is correct answer.
avatar
kelindoan
Joined: 31 Aug 2017
Last visit: 26 Sep 2017
Posts: 7
Own Kudos:
Given Kudos: 11
Posts: 7
Kudos: 8
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
A certain businessman wears only three different colors of shirt - white, blue and grey. The probability that he will wear a blue or grey 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?

(A) 16/81
(B) 2/3
(C) 8/27
(D) 65/81
(E) 19/27

Probability none of the day he would wear White Shirt is (2/3)^4 = 16/81
Probability he would wear white shirt at least once a week is 1-16/81 = 65/81

The Answer is D
User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 27 Apr 2026
Posts: 22,286
Own Kudos:
26,539
 [1]
Given Kudos: 302
Status:Founder & CEO
Affiliations: Target Test Prep
Location: United States (CA)
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 22,286
Kudos: 26,539
 [1]
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
Bunuel
A certain businessman wears only three different colors of shirt - white, blue and grey. The probability that he will wear a blue or grey 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?

(A) 16/81
(B) 2/3
(C) 8/27
(D) 65/81
(E) 19/27

We can use the following equation:

1 = P(wearing white shirt at least once) + P(not wearing white shirt at all)

P(wearing white shirt at least once) = 1 - P(not wearing white shirt at all)

Since P(not wearing white shirt at all) = P(wearing blue or grey shirt all 4 days), that gives us (2/3)^4 = 16/81, and thus:

P(wearing white shirt at least once) = 1 - 16/81 = 65/81

Answer: D
User avatar
Poorvasha
Joined: 11 Jun 2017
Last visit: 17 Apr 2026
Posts: 57
Own Kudos:
Given Kudos: 8
Posts: 57
Kudos: 118
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Probability of not wearing a white shirt = 2/3 (probability of wearing a blue or a grey one)
Probability of this event for 4 days will be 2/3*2/3*2/3*2/3= 16/81
Probability that he wears the white shirt atleast once = 1- 16/81 = 65/81 (D)
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,990
Own Kudos:
Posts: 38,990
Kudos: 1,118
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Automated notice from GMAT Club BumpBot:

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

This post was generated automatically.
Moderators:
Math Expert
109928 posts
Tuck School Moderator
852 posts