Last visit was: 02 Sep 2026, 10:34 It is currently 02 Sep 2026, 10:34
Home
Messages
Tests
Schools
Events
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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
avatar
Somnium
avatar
Joined: 17 May 2018
Last visit: 15 Feb 2019
Posts: 15
Own Kudos:
1
Given Kudos: 8
Posts: 15
Kudos: 1
Help with a question in combinatorics 28 Sep 2018, 01:20
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hello, would much appreciate help with this kind of question :

there are 3 baskets, each with 5 balls.
in first basket we have 4 black balls, 1 yellow.
in second we have 3 black balls, 2 yellow.
in third we have 2 black , 3 yellow.
we pick one ball from each basket. what is the probability that we get at least one black ball ?

thanks

Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
avatar
Gagoosh
avatar
Joined: 23 Nov 2017
Last visit: 02 Oct 2019
Posts: 102
Own Kudos:
184
Given Kudos: 132
Location: Singapore
Concentration: Strategy, Other
Schools: NTU '20 (M) ESSEC '21 (A$)
Schools: NTU '20 (M) ESSEC '21 (A$)
Posts: 102
Kudos: 184
Help with a question in combinatorics 28 Sep 2018, 01:28
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Somnium
Hello, would much appreciate help with this kind of question :

there are 3 baskets, each with 5 balls.
in first basket we have 4 black balls, 1 yellow.
in second we have 3 black balls, 2 yellow.
in third we have 2 black , 3 yellow.
we pick one ball from each basket. what is the probability that we get at least one black ball ?

thanks
Show more


Is the answer 119/125 ?
User avatar
Salsanousi
User avatar
Joined: 19 Oct 2013
Last visit: 29 Dec 2020
Posts: 390
Own Kudos:
360
Given Kudos: 117
Location: Kuwait
GPA: 3.2
WE:Engineering (Real Estate)
Posts: 390
Kudos: 360
Help with a question in combinatorics 28 Sep 2018, 01:43
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Somnium
Hello, would much appreciate help with this kind of question :

there are 3 baskets, each with 5 balls.
in first basket we have 4 black balls, 1 yellow.
in second we have 3 black balls, 2 yellow.
in third we have 2 black , 3 yellow.
we pick one ball from each basket. what is the probability that we get at least one black ball ?

thanks
Show more

Happen to have the answer choices? What is the source for this question?
avatar
Somnium
avatar
Joined: 17 May 2018
Last visit: 15 Feb 2019
Posts: 15
Own Kudos:
1
Given Kudos: 8
Posts: 15
Kudos: 1
Help with a question in combinatorics 28 Sep 2018, 03:33
Kudos
Add Kudos
Bookmarks
Bookmark this Post
in one of official CATs , but unfortunately I don't remember the exact data that was there so I don't know what the answer should be. I changed the stats a bit..
User avatar
ccooley
User avatar
Manhattan Prep Instructor
Joined: 04 Dec 2015
Last visit: 06 Jun 2020
Posts: 931
Own Kudos:
1,665
 [1]
Given Kudos: 115
GMAT 1: 790 Q51 V49
GRE 1: Q170 V170
Expert
Expert reply
GMAT 1: 790 Q51 V49
GRE 1: Q170 V170
Posts: 931
Kudos: 1,665
 [1]
Help with a question in combinatorics 01 Oct 2018, 12:20
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Somnium
Hello, would much appreciate help with this kind of question :

there are 3 baskets, each with 5 balls.
in first basket we have 4 black balls, 1 yellow.
in second we have 3 black balls, 2 yellow.
in third we have 2 black , 3 yellow.
we pick one ball from each basket. what is the probability that we get at least one black ball ?

thanks
Show more

If you see language like 'at least one' in a probability problem, this strategy will usually work. Instead of finding the probability of getting one black ball, then two black balls, then three black balls, you can actually just find the probability of getting all yellow balls, and subtract from 1. You can do that because you're basically looking for the probability that anything other than all yellow is what happens. That'll be the 'opposite' of the probability that you get all yellow.

The probability of getting all yellow balls is 1/5 * 2/5 * 3/5 (the product of the probability of getting a yellow ball from each basket). That equals 6/125.

So, the probability of getting at least one black (in other words, NOT getting all yellow) is 1-6/125 or 119/125.

Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!