GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 14 Oct 2019, 16:08

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

In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20

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

Hide Tags

Find Similar Topics 
Manager
Manager
User avatar
Joined: 22 Mar 2009
Posts: 58
Schools: Darden:Tepper:UCUIC:Kenan Flager:Nanyang:NUS:ISB:UCI Merage:Emory
WE 1: 3
In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20  [#permalink]

Show Tags

New post 02 Nov 2009, 11:59
2
10
00:00
A
B
C
D
E

Difficulty:

  55% (hard)

Question Stats:

54% (01:24) correct 46% (01:43) wrong based on 219 sessions

HideShow timer Statistics

In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20 green balls. How many balls must be taken out in order to make sure we took out 8 of the same color?

a) 8
b) 23
c) 29
d) 32
e) 53

_________________
Second cut is the deepest cut!!!:P
Intern
Intern
avatar
Joined: 06 Oct 2009
Posts: 6
Re: In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20  [#permalink]

Show Tags

New post 02 Nov 2009, 12:23
4
The question asks about how many balls MUST be taken out in order to make sure we took out 8 of the same color.

Now, in this case we have to be sure about our answer when we can say we have taken out 8 balls of same color.

Favorable case will be if we take out first eight balls and all of them are of the same color. But that is a favorable case and may not always be true.

A worst case will be when you are 100% sure that you have achieved the desired result.

As in this case: if you draw out first 28 balls and they are 7 of each color, W, R, B, G.
Now you know that any ball you take out next will be of any one of the above colors and hence you'll have 8 ball of same color.

So ans is 29.

I hope it's clear.
SVP
SVP
User avatar
Joined: 29 Aug 2007
Posts: 1981
Re: In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20  [#permalink]

Show Tags

New post 02 Nov 2009, 23:35
1
kylexy wrote:
In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20 green balls. How many balls must be taken out in order to make sure we took out 8 of the same color?

a) 8
b) 23
c) 29
d) 32
e) 53


Thats 29 in C.

I love these types of questions..
_________________
Verbal: http://gmatclub.com/forum/new-to-the-verbal-forum-please-read-this-first-77546.html
Math: http://gmatclub.com/forum/new-to-the-math-forum-please-read-this-first-77764.html
Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html


GT
Intern
Intern
avatar
Joined: 29 Jul 2009
Posts: 14
Schools: Stanford, HBS, INSEAD
Re: In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20  [#permalink]

Show Tags

New post 03 Nov 2009, 16:44
I don't get why there will be 7 of each when we draw out 28 balls. Could you please elaborate?
Manager
Manager
avatar
Joined: 12 Oct 2009
Posts: 126
Schools: Columbia, INSEAD, RSM, LBS
Re: In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20  [#permalink]

Show Tags

New post 04 Nov 2009, 06:08
Arora2m this one is for you :

Black Blue Yellow Green
1 1 1 1
1 1 1 1
.
.
.
.
.

similar pattern 7 times. the next ball will have to be from either of the colors and making the total tally of that color to 8 balls
Intern
Intern
avatar
Joined: 25 Oct 2009
Posts: 11
Re: In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20  [#permalink]

Show Tags

New post 05 Nov 2009, 09:39
1
HI where do we come across these type of questions in og 11.If you could point out the question numbers it will be really greatful asap.
Director
Director
avatar
Status: There is always something new !!
Affiliations: PMI,QAI Global,eXampleCG
Joined: 08 May 2009
Posts: 860
Re: In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20  [#permalink]

Show Tags

New post 12 May 2011, 04:12
nice question.

take 7 out of each color.7*4 + 1 = 29
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58320
Re: In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20  [#permalink]

Show Tags

New post 12 May 2016, 15:02
Manager
Manager
User avatar
B
Status: IF YOU CAN DREAM IT, YOU CAN DO IT
Joined: 03 Jul 2017
Posts: 187
Location: India
Concentration: Finance, International Business
Re: In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20  [#permalink]

Show Tags

New post 09 Jul 2017, 22:25
Can someone please elaborate the concept in this question. Why do we have to consider each ball of different color??
Director
Director
User avatar
D
Affiliations: IIT Dhanbad
Joined: 13 Mar 2017
Posts: 728
Location: India
Concentration: General Management, Entrepreneurship
GPA: 3.8
WE: Engineering (Energy and Utilities)
Re: In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20  [#permalink]

Show Tags

New post 09 Jul 2017, 23:00
1
kylexy wrote:
In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20 green balls. How many balls must be taken out in order to make sure we took out 8 of the same color?

a) 8
b) 23
c) 29
d) 32
e) 53


This is a very simple question.
Jar contains 15 WB, 25 RB, 10 BB, 20 GB.

Now to ensure that there must be 8 balls of same colour,
the best case will be, we take out 8 ball of same colour &
the worst case will be when we take out 7 balls of each colours and then we take out any ball.
The last ball's colour will be the colour of the 8 balls with same colour and other 7 balls will be of their respective colour.

So to ensure that we have 8 balls of same colour we need to take out 7+7+7 +8 = 29 balls.

Answer C.
_________________
CAT 2017 (98.95) & 2018 (98.91) : 99th percentiler
UPSC Aspirants : Get my app UPSC Important News Reader from Play store.

MBA Social Network : WebMaggu


Appreciate by Clicking +1 Kudos ( Lets be more generous friends.)



What I believe is : "Nothing is Impossible, Even Impossible says I'm Possible" : "Stay Hungry, Stay Foolish".
Target Test Prep Representative
User avatar
D
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8043
Location: United States (CA)
Re: In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20  [#permalink]

Show Tags

New post 12 Jul 2017, 17:05
kylexy wrote:
In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20 green balls. How many balls must be taken out in order to make sure we took out 8 of the same color?

a) 8
b) 23
c) 29
d) 32
e) 53


The worst case scenario would be having to draw 7 balls of each color so that we wouldn’t have 8 balls of any one color. However, if we were to remove just one more ball, regardless of the color, we would then have 8 balls of one color. Thus, we need to remove 7 x 4 + 1 = 29 balls.

Answer: C
_________________

Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
TTP - Target Test Prep Logo
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Director
Director
avatar
G
Joined: 19 Oct 2013
Posts: 520
Location: Kuwait
GPA: 3.2
WE: Engineering (Real Estate)
GMAT ToolKit User
Re: In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20  [#permalink]

Show Tags

New post 30 Oct 2018, 14:20
kylexy wrote:
In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20 green balls. How many balls must be taken out in order to make sure we took out 8 of the same color?

a) 8
b) 23
c) 29
d) 32
e) 53


The maximum we can take out before we have 8 of the same color is 7 of each color.

7 * 4 = 28

Then any additional ball we take will complete a set of 8.

So 29

Answer choice C

Posted from my mobile device
GMAT Club Bot
Re: In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20   [#permalink] 30 Oct 2018, 14:20
Display posts from previous: Sort by

In a jar there are 15 white balls, 25 red balls, 10 blue balls and 20

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne