It is currently 24 Feb 2018, 07:37

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

The length, breadth, and height of a rectangular box are in the ratio

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

Hide Tags

Expert Post
1 KUDOS received
e-GMAT Representative
User avatar
S
Joined: 04 Jan 2015
Posts: 806
The length, breadth, and height of a rectangular box are in the ratio [#permalink]

Show Tags

New post 27 Apr 2017, 22:48
1
This post received
KUDOS
Expert's post
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

81% (01:09) correct 19% (01:12) wrong based on 72 sessions

HideShow timer Statistics

The length, breadth, and height of a rectangular box are in the ratio of 6: 5: 4. If the length is halved, the breadth is doubled and the height is decreased by 50%, what would be percentage change in the volume of the box?


A. 25% increase
B. 25% decrease
C. 50% increase
D. 50% decrease
E. No change in volume.


Thanks,
Saquib
Quant Expert
e-GMAT

Register for our Free Session on Number Properties (held every 3rd week) to solve exciting 700+ Level Questions in a classroom environment under the real-time guidance of our Experts :)

Image
[Reveal] Spoiler: OA

_________________












| '4 out of Top 5' Instructors on gmatclub | 70 point improvement guarantee | www.e-gmat.com


Last edited by EgmatQuantExpert on 30 Apr 2017, 01:55, edited 1 time in total.
Expert Post
e-GMAT Representative
User avatar
S
Joined: 04 Jan 2015
Posts: 806
The length, breadth, and height of a rectangular box are in the ratio [#permalink]

Show Tags

New post 27 Apr 2017, 22:49
The official solution has been posted. Looking forward to a healthy discussion..:)
_________________












| '4 out of Top 5' Instructors on gmatclub | 70 point improvement guarantee | www.e-gmat.com


Last edited by EgmatQuantExpert on 30 Apr 2017, 02:11, edited 1 time in total.
VP
VP
avatar
P
Joined: 22 May 2016
Posts: 1350
Premium Member CAT Tests
Re: The length, breadth, and height of a rectangular box are in the ratio [#permalink]

Show Tags

New post 28 Apr 2017, 12:41
EgmatQuantExpert wrote:
The length, breadth, and height of a rectangular box are in the ratio of 6: 5: 4. If the length is halved, the breadth is doubled and the height is decreased by 100%, what would be percentage change in the volume of the box?


A. 25% increase
B. 25% decrease
C. 50% increase
D. 50% decrease
E. No change in volume.


Thanks,
Saquib
Quant Expert
e-GMAT

"Fools rush in where even angels fear to tread." Even after searching fora to no avail, I have a feeling I'm going to regret this post, but I want to understand what I am missing, not including my reasoning ability at this point.

The question seems to imply some difference between "decreased by" 100% and "decreased 100%." Maybe there exists some diabolical rule that makes no damn sense in plain English. I am entirely confused at this point. Can't wait to see OA.

Running the numbers, and using the formula for percent decrease, I ended up with new H=0, and new volume = 0.

I still can't see the difference between "decreased BY" 100% and "decreased 100%." No matter what height is, let's say 8, to decrease 8 by 100% of 8 means 8-8=0. If height is 8 and decreases 100%, it goes from 8 (minus 100% of itself = 8) = 0

Worse, even when I decided to tangle with phrasing and postulated that if "increased by 100%" meant "double the number," then perhaps "decreased by 100%" meant "halve the number," I got different values for percent decrease with values that, because proportional, should have returned the same percentage decrease.
(Tried it with 6-5-4, got 50% decrease. Tried it with 12-10-8, got 67% decrease.)

100% of any number is itself. To decrease a number BY 100% of that number is to subtract a number by that number. Alternatively, a number that "decreased 100%" similarly started at its full value and "shrunk" by its full value.

Scientists seem to agree with me. For example, see "A STRONG DECREASING TREND IN THE NUMBER OF AMERICAN WIDGEONS WAS IDENTIFIED - The mean number of widgeons decreased by 153 birds from 153 to 0 birds (a decrease by 100 percent) over 20 years, from 1993 to 2012," at http://wakullasprings.org/wp-content/uploads/2014/10/Wildlife-Survey-Analysis-2013-10-03.doc

You'll get answer D if you use numbers 6*5*4 (and use hypo that decreased by 100 = halve the #).

Original volume = 120.
New volume = 3*10*2 = 60
Percent decrease =\(\frac{120-60}{120}\) = \(\frac{60}{120}\) = 50%, which is option D. Why does THIS one work?

Sub-600 question? :?
_________________

At the still point, there the dance is. -- T.S. Eliot
Formerly genxer123


Last edited by generis on 29 Apr 2017, 08:28, edited 1 time in total.
Intern
Intern
avatar
B
Joined: 29 Apr 2017
Posts: 16
Re: The length, breadth, and height of a rectangular box are in the ratio [#permalink]

Show Tags

New post 29 Apr 2017, 08:11
EgmatQuantExpert wrote:
The length, breadth, and height of a rectangular box are in the ratio of 6: 5: 4. If the length is halved, the breadth is doubled and the height is decreased by 100%, what would be percentage change in the volume of the box?


A. 25% increase
B. 25% decrease
C. 50% increase
D. 50% decrease
E. No change in volume.


Thanks,
Saquib
Quant Expert
e-GMAT

Register for our Free Session on Number Properties (held every 3rd week) to solve exciting 700+ Level Questions in a classroom environment under the real-time guidance of our Experts :)

Image


Using same ratio l:b:h::6:5:4

Original volume = 120

New ratio l:b:h::3:10:0

New volume = 0

Hence,
Change in volume = 120-0/120 *100 = 100%

Where am i going wrong?

Thank you

Sent from my SM-N9200 using GMAT Club Forum mobile app
VP
VP
User avatar
P
Status: Learning
Joined: 20 Dec 2015
Posts: 1139
Location: India
Concentration: Operations, Marketing
GMAT 1: 670 Q48 V36
GRE 1: 314 Q157 V157
GPA: 3.4
WE: Manufacturing and Production (Manufacturing)
CAT Tests
Re: The length, breadth, and height of a rectangular box are in the ratio [#permalink]

Show Tags

New post 29 Apr 2017, 09:45
IMO D
Even i failed to understand what does 100% decrease in value mean but i then took a different way to solve the problem.
We are given that the length of a box becomes half that means it is now 50% of its previous value , its breadth is doubled that means 100% increase , then we are given that its height is decreased by 100 %.
So we have volume as a product of length , height and breadth.
Any change in the value of these quantities will reflect in the volume .So we have 50% decrease*100% increase*100% decrease which means that we need 50% more of length to get to our original value.
Hence D is answer.
Please correct me if i am wrong.
_________________

We are more often frightened than hurt; and we suffer more from imagination than from reality

Board of Directors
User avatar
G
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 3326
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)
GMAT ToolKit User Premium Member
Re: The length, breadth, and height of a rectangular box are in the ratio [#permalink]

Show Tags

New post 29 Apr 2017, 10:22
EgmatQuantExpert wrote:
The length, breadth, and height of a rectangular box are in the ratio of 6: 5: 4. If the length is halved, the breadth is doubled and the height is decreased by 100%, what would be percentage change in the volume of the box?


A. 25% increase
B. 25% decrease
C. 50% increase
D. 50% decrease
E. No change in volume


Original Volume is 6*5*4 = 120

Increased Volume is 3*10*2 = 60

Thus, decrease in volume is 60

Percentage change in the volume of the box = 60/120*100 => 50%

Hence, answer must be (D) 50% decrease in volume...
_________________

Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )

1 KUDOS received
Retired Moderator
User avatar
P
Joined: 12 Aug 2015
Posts: 2428
GRE 1: 323 Q169 V154
GMAT ToolKit User Premium Member
Re: The length, breadth, and height of a rectangular box are in the ratio [#permalink]

Show Tags

New post 29 Apr 2017, 21:22
1
This post received
KUDOS
EgmatQuantExpert wrote:
The length, breadth, and height of a rectangular box are in the ratio of 6: 5: 4. If the length is halved, the breadth is doubled andthe height is decreased by 100%, what would be percentage change in the volume of the box?


A. 25% increase
B. 25% decrease
C. 50% increase
D. 50% decrease
E. No change in volume.


Thanks,
Saquib
Quant Expert
e-GMAT



Hi Saquib

Can you please elaborate this statement => "100 percent decrease in height"

How is that ever possible?

If you reduce the height by 100% then the Rectangular Box would cease to Exist.
If that is true.
New volume => Zero

And we none of the options would suffice.
If something gets reduced by 100 percent =>its new value would be Zero.


I hope i am not missing anything.

Regards
Stone Cold



_________________


Getting into HOLLYWOOD with an MBA

Stone Cold's Mock Tests for GMAT-Quant(700+)

Expert Post
e-GMAT Representative
User avatar
S
Joined: 04 Jan 2015
Posts: 806
Re: The length, breadth, and height of a rectangular box are in the ratio [#permalink]

Show Tags

New post 30 Apr 2017, 01:58
stonecold wrote:
EgmatQuantExpert wrote:
The length, breadth, and height of a rectangular box are in the ratio of 6: 5: 4. If the length is halved, the breadth is doubled andthe height is decreased by 100%, what would be percentage change in the volume of the box?


A. 25% increase
B. 25% decrease
C. 50% increase
D. 50% decrease
E. No change in volume.


Thanks,
Saquib
Quant Expert
e-GMAT



Hi Saquib

Can you please elaborate this statement => "100 percent decrease in height"

How is that ever possible?

If you reduce the height by 100% then the Rectangular Box would cease to Exist.
If that is true.
New volume => Zero

And we none of the options would suffice.
If something gets reduced by 100 percent =>its new value would be Zero.


I hope i am not missing anything.

Regards
Stone Cold





Hey Stone Cold,



Apologies for the inconvenience, I somehow missed the updates for this post. The decrease would be 50% and not 100%. I have updated the question.


Regards,
Saquib
_________________












| '4 out of Top 5' Instructors on gmatclub | 70 point improvement guarantee | www.e-gmat.com

Expert Post
2 KUDOS received
e-GMAT Representative
User avatar
S
Joined: 04 Jan 2015
Posts: 806
Re: The length, breadth, and height of a rectangular box are in the ratio [#permalink]

Show Tags

New post 30 Apr 2017, 02:10
2
This post received
KUDOS
Expert's post
Hey Everyone,

Sorry for the mistake. I somehow confused everyone with the "100% decrease" information.

Otherwise the question is very straightforward.

    • Let the length, breadth and height be 6a, 5a and 4a.

    • Therefore, the initial volume of the box \(= 6a * 5a * 4a = 120a^3\).
    • New length \(= 6a * \frac{1}{2} = 3a\)
    • New breadth \(= 5a* 2 = 10a\)
    • New height \(= 4a * \frac{1}{2} = 2a\)
      o Therefore, the New Volume \(= 3a * 10a * 2a = 60a^3\).

    • Thus, Percentage change in volume \(= \frac{(120 – 60)*100}{120} = \frac{1}{2}*100 = 50\)% decrease.

Thus, the correct answer is Option D.


Thanks,
Saquib
Quant Expert
e-GMAT

Register for our Free Session on Number Properties (held every 3rd week) to solve exciting 700+ Level Questions in a classroom environment under the real-time guidance of our Experts :)

Image
_________________












| '4 out of Top 5' Instructors on gmatclub | 70 point improvement guarantee | www.e-gmat.com

Chat Moderator
avatar
P
Joined: 04 Aug 2016
Posts: 596
Location: India
Concentration: Leadership, Strategy
GPA: 4
WE: Engineering (Telecommunications)
Premium Member
Re: The length, breadth, and height of a rectangular box are in the ratio [#permalink]

Show Tags

New post 30 Apr 2017, 18:52
Even with incorrect value initially, many got the correct answer
Re: The length, breadth, and height of a rectangular box are in the ratio   [#permalink] 30 Apr 2017, 18:52
Display posts from previous: Sort by

The length, breadth, and height of a rectangular box are in the ratio

  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®.