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

It is currently 18 Jul 2018, 20:31

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

The value of a precious stone is directly proportional to the cube of

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

Hide Tags

BSchool Forum Moderator
User avatar
V
Joined: 26 Feb 2016
Posts: 2941
Location: India
GPA: 3.12
Premium Member
The value of a precious stone is directly proportional to the cube of [#permalink]

Show Tags

New post 19 Nov 2017, 12:47
1
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

59% (01:24) correct 41% (01:07) wrong based on 49 sessions

HideShow timer Statistics

The value of a precious stone is directly proportional to the cube of its weight. If a big stone broke into three parts in the ratio 1:4:5, what was the percentage drop in the value of the stone?

A. 10%
B. 40%
C. 71%
D. 81%
E. 93%

source: Experts Global

_________________

You've got what it takes, but it will take everything you've got

3 KUDOS received
PS Forum Moderator
avatar
D
Joined: 25 Feb 2013
Posts: 1182
Location: India
GPA: 3.82
GMAT ToolKit User Premium Member Reviews Badge
The value of a precious stone is directly proportional to the cube of [#permalink]

Show Tags

New post 19 Nov 2017, 13:24
3
1
pushpitkc wrote:
The value of a precious stone is directly proportional to the cube of its weight. If a big stone broke into three parts in the ratio 1:4:5, what was the percentage drop in the value of the stone?

A. 10%
B. 40%
C. 71%
D. 81%
E. 93%

source: Experts Global


Let the original weight of the stone be \(10\) units

so original price \(P=10^3k=1000k\), where \(k\) is any constant

as the stone broke in the ratio \(1:4:5\), so the weight of the three stones will be \(1\), \(4\) & \(5\). Revised price will be

\(P_1=1^3k=k\)

\(P_2=4^3k=64k\)

\(P_3=5^3k=125K\)

So Total new price \(= k+64k+125k=190k\)

Hence reduction in price \(= 1000k-190k=810k\)

Reduction % \(= \frac{810k}{1000k}*100=81\)%

Option D
Intern
Intern
User avatar
B
Joined: 16 Aug 2016
Posts: 15
Location: India
GMAT 1: 460 Q35 V19
GPA: 3.6
WE: Brand Management (Retail)
GMAT ToolKit User
Re: The value of a precious stone is directly proportional to the cube of [#permalink]

Show Tags

New post 19 Nov 2017, 13:48
Let's assume initial weight of the precious stone as 10 (1+4+5) and original value as 1000.
As the stone gets broken into 3 parts in the ratio of 1: 4: 5, therefore, the weights of the pieces will be in the same ratio.
Let the value of these 3 pieces be x, y, and z respectively, hence, we get that:
\(\frac{1000}{x}=\frac{10^3}{1^3}\), or, x=1.
Similarly, \(\frac{1000}{y}=\frac{10^3}{4^3}\), giving y=64, and
\(\frac{1000}{z}=\frac{10^3}{5^3}\), giving z=125

Therefore, the new value of the stone will be x+y+z, or, 1+64+125 = 190.

%age change = \(\frac{Old Value - New Value}{Old Value}\)*100

%age change = \(\frac{1000-190}{1000}\)*100 = \(\frac{810}{1000}\)*100 = 81%
Re: The value of a precious stone is directly proportional to the cube of   [#permalink] 19 Nov 2017, 13:48
Display posts from previous: Sort by

The value of a precious stone is directly proportional to the cube of

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

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®.