Last visit was: 22 Apr 2026, 04:50 It is currently 22 Apr 2026, 04:50
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: 22 Apr 2026
Posts: 109,739
Own Kudos:
Given Kudos: 105,819
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,739
Kudos: 810,547
 [15]
1
Kudos
Add Kudos
14
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
JeffTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 04 Mar 2011
Last visit: 05 Jan 2024
Posts: 2,974
Own Kudos:
8,709
 [6]
Given Kudos: 1,646
Status:Head GMAT Instructor
Affiliations: Target Test Prep
Expert
Expert reply
Posts: 2,974
Kudos: 8,709
 [6]
4
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
General Discussion
User avatar
er.arun88
Joined: 02 Jan 2017
Last visit: 30 Jul 2018
Posts: 27
Own Kudos:
65
 [2]
Given Kudos: 92
Location: India
Concentration: Leadership, Marketing
WE:Engineering (Telecommunications)
Posts: 27
Kudos: 65
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
avatar
gmathopeful19
Joined: 09 Oct 2016
Last visit: 27 Jun 2018
Posts: 65
Own Kudos:
Given Kudos: 8
Location: United States
GMAT 1: 740 Q49 V42
GPA: 3.49
Products:
GMAT 1: 740 Q49 V42
Posts: 65
Kudos: 34
Kudos
Add Kudos
Bookmarks
Bookmark this Post
B.

1/3 * 1/3 * 1/3 = 1/27

x/6 = 1/3

x = 2

Posted from my mobile device
User avatar
mohshu
Joined: 21 Mar 2016
Last visit: 26 Dec 2019
Posts: 410
Own Kudos:
Given Kudos: 103
Products:
Posts: 410
Kudos: 143
Kudos
Add Kudos
Bookmarks
Bookmark this Post
1/27= 1/3*1/3*1/3

Prob:
x/6*x/6*x/6

x=2

ans B
User avatar
Mdey
Joined: 13 May 2025
Last visit: 21 Apr 2026
Posts: 8
Given Kudos: 17
Location: India
Concentration: Finance, Entrepreneurship
GMAT Focus 1: 615 Q90 V79 DI73
GMAT Focus 1: 615 Q90 V79 DI73
Posts: 8
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
if out of 6 spheres there are 2 black spheres only, then how could the probability for drawing 3 black sphere is 1/27 ? it is an impossible event... what am I missing here ? please guide.
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 22 Apr 2026
Posts: 109,739
Own Kudos:
810,547
 [1]
Given Kudos: 105,819
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,739
Kudos: 810,547
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Mdey
if out of 6 spheres there are 2 black spheres only, then how could the probability for drawing 3 black sphere is 1/27 ? it is an impossible event... what am I missing here ? please guide.
You are missing “with replacement.” After each draw, the sphere is put back, so the bowl still has 2 black spheres on every draw. That makes getting black three times possible, with probability 2/6 * 2/6 * 2/6 = 1/27.
Moderators:
Math Expert
109739 posts
Tuck School Moderator
853 posts