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

It is currently 19 Aug 2018, 00:40

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

M21-32

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

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 47983
M21-32  [#permalink]

Show Tags

New post 16 Sep 2014, 01:15
2
12
00:00
A
B
C
D
E

Difficulty:

  95% (hard)

Question Stats:

54% (02:41) correct 46% (03:06) wrong based on 98 sessions

HideShow timer Statistics

If 5 dollars and 35 crowns is equivalent to 7 pounds, and 4 dollars and 4 pounds is equivalent to 56 crowns, 1 pound and 28 crowns is equivalent to how many dollars?

A. $7.00
B. $7.50
C. $8.50
D. $9.00
E. $10.00

_________________

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

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 47983
Re M21-32  [#permalink]

Show Tags

New post 16 Sep 2014, 01:15
1
1
Official Solution:

If 5 dollars and 35 crowns is equivalent to 7 pounds, and 4 dollars and 4 pounds is equivalent to 56 crowns, 1 pound and 28 crowns is equivalent to how many dollars?

A. $7.00
B. $7.50
C. $8.50
D. $9.00
E. $10.00


Given:

\(5d+35c=7p\), so \(c=\frac{7p-5d}{35}\);

\(4d+4p=56c\), so \(c=\frac{d+p}{14}\), also if we reduce this equation by 2 we'll get: \(2d+2p=28c\);

From above we have that \(\frac{7p-5d}{35}=\frac{d+p}{14}\), which simplifies to \(p=\frac{5d}{3}\).

Question:

\(p+28c=?\) Since \(2d+2p=28c\), then \(p+28c=p+(2d+2p)=2d+3p=2d+3*\frac{5d}{3}=7d\).


Answer: A
_________________

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

Intern
Intern
avatar
Joined: 17 Sep 2015
Posts: 12
GMAT 1: 760 Q50 V42
GPA: 3.65
Reviews Badge
Re: M21-32  [#permalink]

Show Tags

New post 15 Oct 2015, 15:09
2
Struggling to see how this can be done in 2 min... Bunuel, any thoughts?
Manager
Manager
User avatar
Joined: 18 May 2016
Posts: 67
Concentration: Finance, International Business
GMAT 1: 720 Q49 V39
GPA: 3.7
WE: Analyst (Investment Banking)
Re: M21-32  [#permalink]

Show Tags

New post 30 May 2016, 04:23
I find it very hard to sort of discover which way to take and which variable to try to identify when it comes to questions like this. What is the logic that drives the decision to move c on one side? Any advice? many thanks!
_________________

Please kindly +Kudos if my posts or questions help you!

My debrief: Self-study: How to improve from 620(Q39,V36) to 720(Q49,V39) in 25 days!

Senior Manager
Senior Manager
User avatar
Joined: 18 Jan 2010
Posts: 254
M21-32  [#permalink]

Show Tags

New post 30 May 2016, 04:53
2
2
Bunuel wrote:
If 5 dollars and 35 crowns is equivalent to 7 pounds, and 4 dollars and 4 pounds is equivalent to 56 crowns, 1 pound and 28 crowns is equivalent to how many dollars?

A. $7.00
B. $7.50
C. $8.50
D. $9.00
E. $10.00


Strategy in such questions is to eliminate each variable one by one.

First Form equations:

Eq. 1: 5d+35c = 7p
Eq. 2 : 4d+4p = 56c


Eliminate 1 variable
From eq 1: p = (5/7)d+5c
Put this in Eq 2:

4d+4{(5/7)d+5c} = 56 c

4d+ (20/7)d+ 20 c = 56 c

(48/7) d = 36 c
c = (4/21)d

Express p also in terms of d
p = (5/7)d+5c

p = (5/7)d+ 5 (4/21) d = (15/21) d + (20/21) d = (35/21) d = (5/3)d

Now come to the question once again: 1 pound and 28 crowns is equivalent to how many dollars?

1p+28c = (5/3)d + 28* (4/21) d = (5/3) d + (16/3) d = (21/3) d = 7 d

Answer : A
Intern
Intern
avatar
B
Joined: 12 Jan 2017
Posts: 1
Location: United States
Concentration: Finance, Technology
GMAT 1: 720 Q49 V41
WE: Information Technology (Military & Defense)
Re: M21-32  [#permalink]

Show Tags

New post 30 Mar 2017, 18:49
Why do you decide to solve for C first vice any of the others? Or does it matter? I tried solving for P first and it messed me up.
Manager
Manager
avatar
B
Joined: 23 Nov 2016
Posts: 76
Location: United States (MN)
GMAT 1: 760 Q50 V42
GPA: 3.51
Premium Member
Re: M21-32  [#permalink]

Show Tags

New post 08 Sep 2017, 22:57
Has anyone tried this with Linear Algebra? Trying to find a faster way..
Director
Director
User avatar
S
Joined: 08 Jun 2015
Posts: 529
Location: India
GMAT 1: 640 Q48 V29
GMAT 2: 700 Q48 V38
Premium Member CAT Tests
Re: M21-32  [#permalink]

Show Tags

New post 15 Dec 2017, 09:39
Express the facts given in the two statements as :

5D+35C=7P
4D+4P=56C

We need to find P+28C. Here D stands for dollar, C for Crown , and P for Pound.

Express P in terms of C and C in terms of D. Substitute in P+28C to get the answer as option A.
_________________

" The few , the fearless "

Intern
Intern
avatar
B
Joined: 06 Jul 2015
Posts: 24
Premium Member Reviews Badge
Re: M21-32  [#permalink]

Show Tags

New post 15 Dec 2017, 19:50
I don't know if this is a subtle approach or not; 5,35,7 ,35 is divisible by 7 and 5; 4,4,56 , 56 is divisible by 4 ; 1,28? any number that divides 28, the only number that divides 28 is 7;
Re: M21-32 &nbs [#permalink] 15 Dec 2017, 19:50
Display posts from previous: Sort by

M21-32

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

Moderators: chetan2u, Bunuel

Events & Promotions

PREV
NEXT


GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| 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®.