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

It is currently 17 Aug 2019, 07:56

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 deck of 52 cards, each card is one of 4 different color

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

Hide Tags

Find Similar Topics 
Intern
Intern
avatar
Joined: 17 Aug 2009
Posts: 9
In a deck of 52 cards, each card is one of 4 different color  [#permalink]

Show Tags

New post 28 Aug 2009, 17:21
2
13
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

88% (00:42) correct 12% (00:29) wrong based on 54 sessions

HideShow timer Statistics

In a deck of 52 cards, each card is one of 4 different colors and there are 13 cards of each color. If cards are to be selected at random from the deck, what is the least number of cards that must be selected to ensure that these are at least 3 cards of each color among selected?
Most Helpful Community Reply
Manager
Manager
avatar
Joined: 10 Aug 2009
Posts: 117
Re: Least # of cards  [#permalink]

Show Tags

New post 28 Aug 2009, 20:38
6
1
4
konayuki wrote:
42 is right... but I do not get it.

Help me with the logic!


The logic is the following.
The worst case scenario is that you draw the first 13 cards of the same colour, then another 13 of the same color then another 13 of the same color. After 39 cards, you draw all 3 colors. Then to ensure that you have at least 3 of each, you need to take another 3 cards of the 4th left colour. So in total after 42 card you can be sure you have at least 3 cards of each color (since we considered here the worst case scenario).

By the same logic, if you are asked how many cards you have to draw to ensure you have three of the same colour (not 3 of EACH), the answer is 9.
Here the worst case scenario is that you draw first 4 cards of different colour, then another 4 of different color. After 8 cards, you have two of each colour. So when you draw the 9th card, you are sure you have at least 3 cards of the same colour.
Hope this helps.
General Discussion
Manager
Manager
avatar
Joined: 10 Aug 2009
Posts: 117
Re: Least # of cards  [#permalink]

Show Tags

New post 28 Aug 2009, 18:51
2
nikhilpoddar wrote:
42

Thanks. I didn't notice they ask about three of EACH color. I thought they ask about first three of the same color...If three of each, it is 42.
Intern
Intern
avatar
Joined: 17 Aug 2009
Posts: 9
Re: Least # of cards  [#permalink]

Show Tags

New post 28 Aug 2009, 20:00
1
42 is right... but I do not get it.

Help me with the logic!
CEO
CEO
User avatar
D
Status: GMATINSIGHT Tutor
Joined: 08 Jul 2010
Posts: 2966
Location: India
GMAT: INSIGHT
Schools: Darden '21
WE: Education (Education)
Reviews Badge
In a deck of 52 cards, each card is one of 4 different color  [#permalink]

Show Tags

New post 08 Aug 2015, 07:36
1
konayuki wrote:
In a deck of 52 cards, each card is one of 4 different colors and there are 13 cards of each color. If cards are to be selected at random from the deck, what is the least number of cards that must be selected to ensure that there are at least 3 cards of each color among selected?


Total Cards to be picked (In Worst Case scenario) = 13(All card of First color)+13(All card of Second color)+13(all card of Third color)+2(Both card of Forth color)

i.e. Total cards Picked = 41 and still We don't have 3 cards of each colour

Butthe next card picked will be of forth color and then we will have atleast 3 cards of each colours

i.e. Minimum cards to be picked to ensure the desired scenario = 41+1 = 42 cards
_________________
Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

ACCESS FREE GMAT TESTS HERE:22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION
Intern
Intern
avatar
B
Joined: 13 Apr 2019
Posts: 41
Location: India
Concentration: Marketing, Operations
GPA: 3.5
WE: General Management (Retail)
CAT Tests
Re: In a deck of 52 cards, each card is one of 4 different color  [#permalink]

Show Tags

New post 04 Aug 2019, 04:51
konayuki wrote:
In a deck of 52 cards, each card is one of 4 different colors and there are 13 cards of each color. If cards are to be selected at random from the deck, what is the least number of cards that must be selected to ensure that these are at least 3 cards of each color among selected?


42.

worst case + 1

(13+13+13+2)+1
GMAT Club Bot
Re: In a deck of 52 cards, each card is one of 4 different color   [#permalink] 04 Aug 2019, 04:51
Display posts from previous: Sort by

In a deck of 52 cards, each card is one of 4 different color

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





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