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

It is currently 20 Aug 2019, 20:38

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

Melinda's lights went out. She has 3 pairs of red socks in her drawer

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

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 57155
Melinda's lights went out. She has 3 pairs of red socks in her drawer  [#permalink]

Show Tags

New post 30 Jul 2019, 00:27
00:00
A
B
C
D
E

Difficulty:

  65% (hard)

Question Stats:

43% (00:58) correct 57% (01:41) wrong based on 67 sessions

HideShow timer Statistics

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 57155
Re: Melinda's lights went out. She has 3 pairs of red socks in her drawer  [#permalink]

Show Tags

New post 30 Jul 2019, 00:29
Director
Director
User avatar
P
Joined: 03 Jun 2019
Posts: 955
Location: India
Melinda's lights went out. She has 3 pairs of red socks in her drawer  [#permalink]

Show Tags

New post Updated on: 30 Jul 2019, 08:47
Bunuel wrote:
Melinda's lights went out. She has 3 pairs of red socks in her drawer, 2 pairs of black socks, and 5 pairs of white socks. What is the minimum number of pairs she must remove from the drawer to ensure that she has a pair of each color?

A. 3
B. 5
C. 7
D. 9
E. 10


She has to take out = 5 W + 3 R + 1 B = 9 pairs

IMO D
_________________
"Success is not final; failure is not fatal: It is the courage to continue that counts."

Please provide kudos if you like my post. Kudos encourage active discussions.

My GMAT Resources: -

Efficient Learning

Tele: +91-11-40396815
Mobile : +91-9910661622
E-mail : kinshook.chaturvedi@gmail.com

Originally posted by Kinshook on 30 Jul 2019, 00:42.
Last edited by Kinshook on 30 Jul 2019, 08:47, edited 1 time in total.
GMAT Club Legend
GMAT Club Legend
User avatar
D
Joined: 18 Aug 2017
Posts: 4491
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
GMAT ToolKit User Premium Member CAT Tests
Re: Melinda's lights went out. She has 3 pairs of red socks in her drawer  [#permalink]

Show Tags

New post 30 Jul 2019, 08:45
Bunuel wrote:
Melinda's lights went out. She has 3 pairs of red socks in her drawer, 2 pairs of black socks, and 5 pairs of white socks. What is the minimum number of pairs she must remove from the drawer to ensure that she has a pair of each color?

A. 3
B. 5
C. 7
D. 9
E. 10


total pairs 10
red ; 3 , black 2 and white ; 5
so she would have to take out 5 white+ 3 red + 1 black ; 9 pairs to ensure that she ends up with a pair of same color
IMO D
_________________
If you liked my solution then please give Kudos. Kudos encourage active discussions.
Manager
Manager
User avatar
G
Joined: 08 Jan 2018
Posts: 127
Re: Melinda's lights went out. She has 3 pairs of red socks in her drawer  [#permalink]

Show Tags

New post 30 Jul 2019, 08:59
1
We need at least 1 pair of each color.

We have-

Red- I I I
Black- I I
White- I I I I I

Let's consider the worst-case scenario:
We pick up 5 - All turn out to be White
Then we pick up 3 more - All turn out to be Red.
So, till now we picked up 8 socks and have pairs of 2 colors (White and Red).

The 9th one we pick - Has to be Black (as it will be the only color left).

Hence, Melinda needs to remove a minimum of 9 pair from the drawer to ensure that she has a pair of each color.

Answer D
Senior Manager
Senior Manager
avatar
P
Joined: 05 Jul 2018
Posts: 346
Location: India
Concentration: General Management, Technology
GMAT 1: 600 Q47 V26
GRE 1: Q162 V149
GPA: 3.6
WE: Information Technology (Consulting)
Reviews Badge CAT Tests
Re: Melinda's lights went out. She has 3 pairs of red socks in her drawer  [#permalink]

Show Tags

New post 30 Jul 2019, 09:31
In worst case, Melida may have 5 pairs of white , 3 pairs of red and 1 pair of black socks to ensure that she has at least 1 pair of each color.

Total pairs= 5+3+1=9

Hence, IMO D is the answer
_________________
Intern
Intern
avatar
B
Joined: 18 Jun 2017
Posts: 3
Re: Melinda's lights went out. She has 3 pairs of red socks in her drawer  [#permalink]

Show Tags

New post 31 Jul 2019, 01:08
If someone could help me here, I don't understand why we are considering the worst case scenario for minimum number of pairs.

If the question says maximum number of pairs to remove to get each coloured pair then it should be 9, while minimum should be 3 ( the best case )
Senior Manager
Senior Manager
avatar
P
Joined: 05 Jul 2018
Posts: 346
Location: India
Concentration: General Management, Technology
GMAT 1: 600 Q47 V26
GRE 1: Q162 V149
GPA: 3.6
WE: Information Technology (Consulting)
Reviews Badge CAT Tests
Re: Melinda's lights went out. She has 3 pairs of red socks in her drawer  [#permalink]

Show Tags

New post 31 Jul 2019, 04:07
1
ogmega wrote:
If someone could help me here, I don't understand why we are considering the worst case scenario for minimum number of pairs.

If the question says maximum number of pairs to remove to get each coloured pair then it should be 9, while minimum should be 3 ( the best case )


If it was.just ,3 you could have taken out all 3 from.the.5 pairs of same color.

Rephrase the question as ...Minimum numbers of socks I must pick to be 100% sure that I got at least one pair of each color

For doing that I need all 5+ all 3 and 1 more(for the third.color

Even if I choose 8 not 9 I may still be choosing just 5 pairs of first color and 3 pairs of second color and not end up getting one pair of each color.

Hope this helps

Posted from my mobile device
_________________
Intern
Intern
avatar
Joined: 30 Jun 2019
Posts: 4
Re: Melinda's lights went out. She has 3 pairs of red socks in her drawer  [#permalink]

Show Tags

New post 31 Jul 2019, 16:17
I think this question is worded poorly.
"What is the minimum number of pairs she must remove from the drawer to ensure that she has a pair of each color?"
I interpreted this as "how many does she have to remove from the drawer to ensure she has a pair of each in the drawer?".

Also, as other people have pointed about, the best case scenario from take out socks (and ending up with a pair of each outside the drawer) would be 3. But this is missing the "certainty" part of this question. Recommend rephrasing to "What is the minimum number of pairs she must remove from the drawer to ensure that she has a pair of each color with 100% certainty?"
Target Test Prep Representative
User avatar
D
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 7412
Location: United States (CA)
Re: Melinda's lights went out. She has 3 pairs of red socks in her drawer  [#permalink]

Show Tags

New post 05 Aug 2019, 19:21
Bunuel wrote:
Melinda's lights went out. She has 3 pairs of red socks in her drawer, 2 pairs of black socks, and 5 pairs of white socks. What is the minimum number of pairs she must remove from the drawer to ensure that she has a pair of each color?

A. 3
B. 5
C. 7
D. 9
E. 10


If she removes 8 pairs of socks, she might have all 3 pairs of red socks and all 5 pairs of white socks, but no pairs of black socks. However, if she removes 1 more pair of socks, she will have a pair of socks of each color since the final pair of socks must be a matching black pair.

Answer: D
_________________

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.

Intern
Intern
avatar
B
Joined: 13 Mar 2019
Posts: 27
CAT Tests
Re: Melinda's lights went out. She has 3 pairs of red socks in her drawer  [#permalink]

Show Tags

New post 08 Aug 2019, 20:51
1
Since we need to be sure, so we will go for the worst case scenario -
First 5 pair drawn are all white,
Next 3 drawn are all red,
Now certainly one more pair drawn and we have all the three pairs.
So the Answer is 5+3+1 = 9
GMAT Club Bot
Re: Melinda's lights went out. She has 3 pairs of red socks in her drawer   [#permalink] 08 Aug 2019, 20:51
Display posts from previous: Sort by

Melinda's lights went out. She has 3 pairs of red socks in her drawer

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





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