It is currently 21 Jan 2018, 01:00

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Sally has five red cards numbered 1 through 5 and four blue

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

Hide Tags

Director
Director
avatar
Joined: 29 Nov 2012
Posts: 860

Kudos [?]: 1539 [0], given: 543

Sally has five red cards numbered 1 through 5 and four blue [#permalink]

Show Tags

New post 05 Oct 2013, 03:08
14
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  75% (hard)

Question Stats:

61% (02:22) correct 39% (02:29) wrong based on 173 sessions

HideShow timer Statistics

Sally has five red cards numbered 1 through 5 and four blue cards numbered 3 through 6. She stacks the cards so that the colors alternate and so that the number on each red card divides evenly into the number on each neighboring blue card. What is the sum of the numbers on the middle three cards?

A. 8
B. 9
C. 10
D. 11
E. 12
[Reveal] Spoiler: OA

_________________

Click +1 Kudos if my post helped...

Amazing Free video explanation for all Quant questions from OG 13 and much more http://www.gmatquantum.com/og13th/

GMAT Prep software What if scenarios http://gmatclub.com/forum/gmat-prep-software-analysis-and-what-if-scenarios-146146.html


Last edited by Bunuel on 05 Oct 2013, 03:27, edited 2 times in total.
Edited the question.

Kudos [?]: 1539 [0], given: 543

Expert Post
6 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43334

Kudos [?]: 139638 [6], given: 12794

Re: Sally has five red cards numbered 1 through 5 and four blue [#permalink]

Show Tags

New post 05 Oct 2013, 03:26
6
This post received
KUDOS
Expert's post
2
This post was
BOOKMARKED
fozzzy wrote:
Sally has five red cards numbered 1 through 5 and four blue cards numbered 3 through 6. She stacks the cards so that the colors alternate and so that the number on each red card divides evenly into the number on each neighboring blue card. What is the sum of the numbers on the middle three cards??

A) 8
B) 9
C) 10
D) 11
E) 12


The cards are stacked so that the colors alternate: R-B-R-B-R-B-R-B-R.

We are also told that the number on each red card divides evenly into the number on each neighboring blue card.

There are two primes in Blue cards: 3 and 5. Their divisors are 1 and 3 AND 1 and 5, respectively. Thus R1 must be between R3 and R5, R3 must be by B3 and R5 must be by B5: 3-3-1-5-5.

Next, add multiple of 3 to the left of 3: 6-3-3-1-5-5.

Add factor of 6 to the left of 6: 2-6-3-3-1-5-5.

Add multiple of 2 to the left of 2: 4-2-6-3-3-1-5-5.

And finally add factor of 4 to the left of 4: 4-4-2-6-3-3-1-5-5.

The sum of the numbers on the middle three cards is 6+3+3=12.

Answer: E.

Hope it's clear.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 139638 [6], given: 12794

Intern
Intern
avatar
Joined: 23 Jul 2013
Posts: 21

Kudos [?]: 9 [0], given: 63

GMAT ToolKit User
Re: Sally has five red cards numbered 1 through 5 and four blue [#permalink]

Show Tags

New post 16 Oct 2013, 23:10
Bunuel wrote:
fozzzy wrote:
Sally has five red cards numbered 1 through 5 and four blue cards numbered 3 through 6. She stacks the cards so that the colors alternate and so that the number on each red card divides evenly into the number on each neighboring blue card. What is the sum of the numbers on the middle three cards??

A) 8
B) 9
C) 10
D) 11
E) 12


The cards are stacked so that the colors alternate: R-B-R-B-R-B-R-B-R.

We are also told that the number on each red card divides evenly into the number on each neighboring blue card.

There are two primes in Blue cards: 3 and 5. Their divisors are 1 and 3 AND 1 and 5, respectively. Thus R1 must be between R3 and R5, R3 must be by B3 and R5 must be by B5: 3-3-1-5-5.

Next, add multiple of 3 to the left of 3: 6-3-3-1-5-5.

Add factor of 6 to the left of 6: 2-6-3-3-1-5-5.

Add multiple of 2 to the left of 2: 4-2-6-3-3-1-5-5.

And finally add factor of 4 to the left of 4: 4-4-2-6-3-3-1-5-5.

The sum of the numbers on the middle three cards is 6+3+3=12.

Answer: E.

Hope it's clear.


Hi Bunuel, Does such questions actualy appear on GMAT..?? its really tough and makes my mind wooof..!!

Kudos [?]: 9 [0], given: 63

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43334

Kudos [?]: 139638 [0], given: 12794

Re: Sally has five red cards numbered 1 through 5 and four blue [#permalink]

Show Tags

New post 17 Oct 2013, 02:11
ishdeep18 wrote:
Bunuel wrote:
fozzzy wrote:
Sally has five red cards numbered 1 through 5 and four blue cards numbered 3 through 6. She stacks the cards so that the colors alternate and so that the number on each red card divides evenly into the number on each neighboring blue card. What is the sum of the numbers on the middle three cards??

A) 8
B) 9
C) 10
D) 11
E) 12


The cards are stacked so that the colors alternate: R-B-R-B-R-B-R-B-R.

We are also told that the number on each red card divides evenly into the number on each neighboring blue card.

There are two primes in Blue cards: 3 and 5. Their divisors are 1 and 3 AND 1 and 5, respectively. Thus R1 must be between R3 and R5, R3 must be by B3 and R5 must be by B5: 3-3-1-5-5.

Next, add multiple of 3 to the left of 3: 6-3-3-1-5-5.

Add factor of 6 to the left of 6: 2-6-3-3-1-5-5.

Add multiple of 2 to the left of 2: 4-2-6-3-3-1-5-5.

And finally add factor of 4 to the left of 4: 4-4-2-6-3-3-1-5-5.

The sum of the numbers on the middle three cards is 6+3+3=12.

Answer: E.

Hope it's clear.


Hi Bunuel, Does such questions actualy appear on GMAT..?? its really tough and makes my mind wooof..!!


Yes, the question is hard, though I think you can expect such questions if you are doing well on the test.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 139638 [0], given: 12794

Intern
Intern
avatar
Joined: 30 Sep 2013
Posts: 22

Kudos [?]: 16 [0], given: 4

Re: Sally has five red cards numbered 1 through 5 and four blue [#permalink]

Show Tags

New post 12 Mar 2014, 07:53
Bunuel wrote:
fozzzy wrote:
Sally has five red cards numbered 1 through 5 and four blue cards numbered 3 through 6. She stacks the cards so that the colors alternate and so that the number on each red card divides evenly into the number on each neighboring blue card. What is the sum of the numbers on the middle three cards??

A) 8
B) 9
C) 10
D) 11
E) 12


The cards are stacked so that the colors alternate: R-B-R-B-R-B-R-B-R.

We are also told that the number on each red card divides evenly into the number on each neighboring blue card.

There are two primes in Blue cards: 3 and 5. Their divisors are 1 and 3 AND 1 and 5, respectively. Thus R1 must be between R3 and R5, R3 must be by B3 and R5 must be by B5: 3-3-1-5-5.

Next, add multiple of 3 to the left of 3: 6-3-3-1-5-5.

Add factor of 6 to the left of 6: 2-6-3-3-1-5-5.

Add multiple of 2 to the left of 2: 4-2-6-3-3-1-5-5.

And finally add factor of 4 to the left of 4: 4-4-2-6-3-3-1-5-5.

The sum of the numbers on the middle three cards is 6+3+3=12.

Answer: E.

Hope it's clear.




Hi bunuel,

I am not able to understand the logic behind the sequence.
Why it can't be like this
2-6-3-3-4-4-1-5-5

And have sum as 3+4+4 = 11

Or any other combination

Kudos [?]: 16 [0], given: 4

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43334

Kudos [?]: 139638 [0], given: 12794

Re: Sally has five red cards numbered 1 through 5 and four blue [#permalink]

Show Tags

New post 12 Mar 2014, 08:30
riteshgmat wrote:
Bunuel wrote:
fozzzy wrote:
Sally has five red cards numbered 1 through 5 and four blue cards numbered 3 through 6. She stacks the cards so that the colors alternate and so that the number on each red card divides evenly into the number on each neighboring blue card. What is the sum of the numbers on the middle three cards??

A) 8
B) 9
C) 10
D) 11
E) 12


The cards are stacked so that the colors alternate: R-B-R-B-R-B-R-B-R.

We are also told that the number on each red card divides evenly into the number on each neighboring blue card.

There are two primes in Blue cards: 3 and 5. Their divisors are 1 and 3 AND 1 and 5, respectively. Thus R1 must be between R3 and R5, R3 must be by B3 and R5 must be by B5: 3-3-1-5-5.

Next, add multiple of 3 to the left of 3: 6-3-3-1-5-5.

Add factor of 6 to the left of 6: 2-6-3-3-1-5-5.

Add multiple of 2 to the left of 2: 4-2-6-3-3-1-5-5.

And finally add factor of 4 to the left of 4: 4-4-2-6-3-3-1-5-5.

The sum of the numbers on the middle three cards is 6+3+3=12.

Answer: E.

Hope it's clear.




Hi bunuel,

I am not able to understand the logic behind the sequence.
Why it can't be like this
2-6-3-3-4-4-1-5-5

And have sum as 3+4+4 = 11

Or any other combination


Your sequence is not possible because it violates the condition that the number on each red card divides evenly into the number on each neighboring blue card.

2-6-3-3-4-4-1-5-5 --> 4 there is NOT a factor of neighboring 3.

While in the following sequence 4-4-2-6-3-3-1-5-5 the number on EACH red card is a factor of EACH neighboring blue card.

Hope it's clear.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 139638 [0], given: 12794

1 KUDOS received
Manager
Manager
User avatar
Joined: 04 Sep 2012
Posts: 100

Kudos [?]: 50 [1], given: 504

Location: Philippines
Concentration: Marketing, Entrepreneurship
Schools: Ross (Michigan) - Class of 2017
GMAT 1: 620 Q48 V27
GMAT 2: 660 Q47 V34
GMAT 3: 700 Q47 V38
GPA: 3.25
WE: Sales (Manufacturing)
GMAT ToolKit User
Sally has five red cards numbered 1 through 5 and four blue [#permalink]

Show Tags

New post 30 Jul 2014, 01:06
1
This post received
KUDOS
1
This post was
BOOKMARKED
fozzzy wrote:
Sally has five red cards numbered 1 through 5 and four blue cards numbered 3 through 6. She stacks the cards so that the colors alternate and so that the number on each red card divides evenly into the number on each neighboring blue card. What is the sum of the numbers on the middle three cards?

A. 8
B. 9
C. 10
D. 11
E. 12


1,2,3,4,5
3,4,5,6

Rule states that the red card must be a multiple of the 2 blue cards next to it. Therefore, we should start off with the most multiple (6)
2-6-3

1,2,3,4,5
3,4,5,6
We should then attempt to connect 2 & 3 with a multiple among the remaining red cards
4-2-6-3-3

1,2,3,4,5
3,4,5,6
We then need to look for a factor of 4 & 3.
4-4-2-6-3-3-1

1,2,3,4,5
3,4,5,6
Fill in missing Blue 5 & Red 5 on the far right side
4-4-2-6-3-3-1-5-5

We are looking for the sum of the 3 middle digits.
4-4-2-6-3-3-1-5-5

6+3+3=12

Answer is E

Kudos [?]: 50 [1], given: 504

Intern
Intern
avatar
B
Joined: 15 Oct 2017
Posts: 16

Kudos [?]: 1 [0], given: 183

GMAT 1: 630 Q39 V38
Re: Sally has five red cards numbered 1 through 5 and four blue [#permalink]

Show Tags

New post 04 Dec 2017, 23:09
Why can't it be 3-3-6-2-4-4-1-5-5

Sum here equals 10.

Kudos [?]: 1 [0], given: 183

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43334

Kudos [?]: 139638 [0], given: 12794

Re: Sally has five red cards numbered 1 through 5 and four blue [#permalink]

Show Tags

New post 04 Dec 2017, 23:13
Expert's post
1
This post was
BOOKMARKED
strawhat316 wrote:
Why can't it be 3-3-6-2-4-4-1-5-5

Sum here equals 10.


You should read a question and solution more carefully.

Your sequence is not possible because it violates the condition that the number on each red card divides evenly into the number on each neighboring blue card.

3-3-6-2-4-4-1-5-5 --> 6, 4, and 1 are NOT factor of neighbouring cards.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 139638 [0], given: 12794

Intern
Intern
avatar
B
Joined: 15 Oct 2017
Posts: 16

Kudos [?]: 1 [0], given: 183

GMAT 1: 630 Q39 V38
Re: Sally has five red cards numbered 1 through 5 and four blue [#permalink]

Show Tags

New post 04 Dec 2017, 23:17
Got it. I got confused about the order. Thanks Bunuel

Sent from my ONE A2003 using GMAT Club Forum mobile app

Kudos [?]: 1 [0], given: 183

Re: Sally has five red cards numbered 1 through 5 and four blue   [#permalink] 04 Dec 2017, 23:17
Display posts from previous: Sort by

Sally has five red cards numbered 1 through 5 and four blue

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


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

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

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.