Last visit was: 20 Jul 2025, 08:49 It is currently 20 Jul 2025, 08:49
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
timmaxwell8
Joined: 08 Oct 2009
Last visit: 14 Oct 2009
Posts: 9
Own Kudos:
69
 [35]
Given Kudos: 1
Posts: 9
Kudos: 69
 [35]
Kudos
Add Kudos
35
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 19 Jul 2025
Posts: 102,627
Own Kudos:
Given Kudos: 98,235
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 102,627
Kudos: 742,994
 [10]
6
Kudos
Add Kudos
3
Bookmarks
Bookmark this Post
General Discussion
User avatar
gmatjon
Joined: 18 Aug 2009
Last visit: 21 Jul 2013
Posts: 216
Own Kudos:
357
 [1]
Given Kudos: 16
Concentration: Accounting
Schools:UT at Austin, Indiana State University, UC at Berkeley
 Q47  V34 GMAT 2: 660  Q46  V35 GMAT 3: 700  Q49  V36
GPA: 3.8
WE 1: 5.5
WE 2: 5.5
WE 3: 6.0
GMAT 1: 700 Q49 V36
Posts: 216
Kudos: 357
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
bhushan252
Joined: 18 Jul 2009
Last visit: 19 Nov 2009
Posts: 70
Own Kudos:
269
 [1]
Given Kudos: 37
Location: India
Concentration: Marketing
Schools:South Asian B-schools
 Q48  V18
Posts: 70
Kudos: 269
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I agree...only logic will help

take out 4G + 4B + 1R = 9 marbles
User avatar
srichaks
Joined: 12 May 2005
Last visit: 05 Oct 2013
Posts: 23
Own Kudos:
50
 [1]
Posts: 23
Kudos: 50
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
What about scenario of choosing 3 red and 4 blue and still seeing distinct color.
In other words why can't we have 8 marbles drawn and still see three distinct colors? 3red+4 blue=7 marbles and on 8th draw should be green since remaining should be all green marbles?

Can someone please explain why?

Thanks in advance.
User avatar
nphilli1
Joined: 24 May 2010
Last visit: 02 Oct 2013
Posts: 9
Own Kudos:
153
 [1]
Given Kudos: 1
Posts: 9
Kudos: 153
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
srichaks
What about scenario of choosing 3 red and 4 blue and still seeing distinct color.
In other words why can't we have 8 marbles drawn and still see three distinct colors? 3red+4 blue=7 marbles and on 8th draw should be green since remaining should be all green marbles?

Can someone please explain why?

Thanks in advance.

The word "ensure" in the question basically is asking in the worst case scenario. So yes technically, the scenario outlined above is true as well, it is not the worst possible outcome.

In order to guarantee the outcome of one of each color, you need to take into account all of the balls in the two largest groups which equals 8.

Hope that helped.
avatar
Manjari22
Joined: 23 Dec 2012
Last visit: 13 Mar 2014
Posts: 7
Own Kudos:
7
 [2]
Given Kudos: 5
Location: United States
Concentration: Technology, Entrepreneurship
GMAT 1: 670 Q48 V34
GPA: 3.85
WE:Analyst (Computer Software)
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
What is the difference between this question and the one below.Please explain its confusing:

There are 15 black chips and 5 white chips in a jar. What is the least number of chips we should pick to guarantee that we have 2 chips of the same color?
A. 3
B. 5
C. 6
D. 16
E. 19

Worst case scenario would be if the first two chips we pick will be of the different colors. But the next chip must match with either of two, so 3 is the answer.

Answer: A.
User avatar
azhrhasan
Joined: 13 Apr 2019
Last visit: 13 Sep 2024
Posts: 122
Own Kudos:
Given Kudos: 93
Location: Canada
Concentration: Marketing, Operations
GMAT 1: 690 Q49 V35
GPA: 3.5
WE:General Management (Retail: E-commerce)
Products:
GMAT 1: 690 Q49 V35
Posts: 122
Kudos: 164
Kudos
Add Kudos
Bookmarks
Bookmark this Post
timmaxwell8
In his pocket, a boy has 3 red marbles, 4 blue marbles, and 4 green marbles. How many will he have to take out of his pocket to ensure that he has taken out at least one of each color?

A. 3
B. 7
C. 8
D. 9
E. 11

9 (4+4+1) worst case
avatar
sarphant
Joined: 13 Mar 2019
Last visit: 12 Oct 2019
Posts: 21
Own Kudos:
12
 [1]
Given Kudos: 33
Posts: 21
Kudos: 12
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
In Such cases, Go for the worst case scenario and hence here we can assume that balls drawn first is (Blue or Green) = 4 and then a single ball to make sure that the guy has atleast one ball of each color which is +1.

Hence the answer is 4+4+1 = 9
User avatar
akadiyan
User avatar
Retired Moderator
Joined: 31 May 2017
Last visit: 20 Jun 2025
Posts: 740
Own Kudos:
Given Kudos: 53
Concentration: Technology, Strategy
Products:
Posts: 740
Kudos: 696
Kudos
Add Kudos
Bookmarks
Bookmark this Post
In his pocket, a boy has 3 red marbles, 4 blue marbles, and 4 green marbles. How many will he have to take out of his pocket to ensure that he has taken out at least one of each color?

We need to maximise the possibility of worst case scenario's.

Consider that first 4 draws can be from green and next 4 can be from blue marbles, even then not all color is represented, but the next card has to be Blue and thus all colors are represented.

So 8 unsucessful draws (4B + 4G) + 1 Blue = 9

Ans: D
User avatar
karnavora1
Joined: 29 Feb 2020
Last visit: 03 Nov 2024
Posts: 78
Own Kudos:
97
 [2]
Given Kudos: 13
Location: India
Concentration: Marketing, International Business
GMAT 1: 600 Q42 V31
Products:
GMAT 1: 600 Q42 V31
Posts: 78
Kudos: 97
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
In his pocket, a boy has 3 red marbles, 4 blue marbles, and 4 green marbles. How many will he have to take out of his pocket to ensure that he has taken out at least one of each color?

A. 3
B. 7
C. 8
D. 9
He can start with 3 red, 4 blue and then 1 green but that is not the worst case scenario, the worst case scenario is that he starts with 4 green, 4 blue and finally 1 red, making it 9 marbles.
E. 11
User avatar
Taiye745
Joined: 11 May 2023
Last visit: 08 Jan 2024
Posts: 1
Posts: 1
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
In his pocket, a boy has 3 red marbles, 4 blue marbles, and 4 green marbles. How many will he have to take out of his pocket to ensure that he has taken out at least one of each color?

To ensure that the boy has taken out at least one marble of each color, we need to consider the worst-case scenario where he takes out the maximum number of marbles of the same color before getting one of each color.

In this case, the boy would need to take out all the marbles of two colors (red and blue or red and green) before he can be certain to have at least one of each color.

To calculate the minimum number of marbles he needs to take out, we add up the number of marbles of the two colors he has the most of, which are red and blue:

3 red marbles + 4 blue marbles = 7 marbles.

Therefore, the boy would need to take out at least 7 marbles from his pocket to ensure that he has taken out at least one marble of each color.

Posted from my mobile device
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 37,461
Own Kudos:
Posts: 37,461
Kudos: 1,013
Kudos
Add Kudos
Bookmarks
Bookmark this Post
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.
Moderators:
Math Expert
102627 posts
PS Forum Moderator
700 posts