Find all School-related info fast with the new School-Specific MBA Forum
Learn more about the recent changes... close

It is currently 18 May 2013, 04:52
Customize  |  Hide

Search
Register
New posts
Unanswered

The useful life of a certain piece of equipment is

  Question banks Downloads My Bookmarks Reviews  
  Oldest Best Reply
Search for:
 
Print view
First unread post
Author Message
TAGS:
CEO
CEO
User avatar
Joined: 21 Jan 2007
Posts: 2797
Location: New York City
Followers: 5

Kudos [?]: 132 [0], given: 4

GMAT Tests User
The useful life of a certain piece of equipment is [#permalink] New post 20 Feb 2008, 15:00
The useful life of a certain piece of equipment is determined by the following formula: u =(8d)/h2, where u is the useful life of the equipment, in years, d is the density of the underlying material, in g/cm3, and h is the number of hours of daily usage of the equipment. If the density of the underlying material is doubled and the daily usage of the equipment is halved, what will be the percentage increase in the useful life of the equipment?

300%
400%
600%
700%
800%
_________________

You tried your best and you failed miserably. The lesson is 'never try'. -Homer Simpson

Director
Director
Joined: 01 Jan 2008
Posts: 635
Followers: 3

Kudos [?]: 114 [0], given: 1

GMAT Tests User
Re: MGMAT - Formula [#permalink] New post 20 Feb 2008, 15:09
bmwhype2 wrote:
The useful life of a certain piece of equipment is determined by the following formula: u =(8d)/h2, where u is the useful life of the equipment, in years, d is the density of the underlying material, in g/cm3, and h is the number of hours of daily usage of the equipment. If the density of the underlying material is doubled and the daily usage of the equipment is halved, what will be the percentage increase in the useful life of the equipment?

300%
400%
600%
700%
800%


if it's h^2 then D is the answer
I really don't like units though :)
Senior Manager
Senior Manager
User avatar
Joined: 20 Dec 2004
Posts: 268
Followers: 6

Kudos [?]: 43 [0], given: 0

GMAT Tests User
Re: MGMAT - Formula [#permalink] New post 20 Feb 2008, 15:09
bmwhype2 wrote:
The useful life of a certain piece of equipment is determined by the following formula: u =(8d)/h2, where u is the useful life of the equipment, in years, d is the density of the underlying material, in g/cm3, and h is the number of hours of daily usage of the equipment. If the density of the underlying material is doubled and the daily usage of the equipment is halved, what will be the percentage increase in the useful life of the equipment?

300%
400%
600%
700%
800%


I am assuming your question is u =(8d)/h^2,

Hence new equation would be
u_1 = \frac{8 * (2d)}{(\frac{h}{2})^2} --> u_1 = 8 * \frac{8 * d} {({h})^2} --> u_1 = 8*u

Hence 700% increase....
_________________

Stay Hungry, Stay Foolish

SVP
SVP
Joined: 28 Dec 2005
Posts: 1612
Followers: 1

Kudos [?]: 53 [0], given: 2

GMAT Tests User
Re: MGMAT - Formula [#permalink] New post 20 Feb 2008, 19:01
agreed. assuming question is h^2, we have:

percentage change = u2-u1/u2 * 100

u1=8d/h^2

u2=[8*2d]/[(h/2)^2] -->64d/h^2

64d/h^2 - 8d/h^2 / 8d/h^2 = 7*100 = 700%
Director
Director
Joined: 30 Jun 2007
Posts: 793
Followers: 1

Kudos [?]: 82 [0], given: 0

GMAT Tests User
Re: MGMAT - Formula [#permalink] New post 21 Feb 2008, 02:42
U = (8d) / h2 without any percentage change
D = 1 h = 1
Uold = 4
With change
Unew = 16d / h
D = 1 h = 1
Unew = 16

400%
Re: MGMAT - Formula   [#permalink] 21 Feb 2008, 02:42
    Similar topics Author Replies Last post
Similar
Topics:
 New posts EXPERTS_POSTS_IN_THIS_TOPIC Happy Life from all of us. Curly05 2 31 Jul 2003, 19:47
New posts A rope of 40 meter long cut into 2 pieces, one piece is used SunShine 2 09 Feb 2006, 07:42
New posts useful life skim 1 27 Jun 2009, 11:36
This topic is locked, you cannot edit posts or make further replies. New EXPERTS_POSTS_IN_THIS_TOPIC The useful life of a certain piece of equipment is kairoshan 5 18 Nov 2009, 21:47
New posts 1 EXPERTS_POSTS_IN_THIS_TOPIC The useful life of a certain piece of equipment is determine bruiz 4 22 Sep 2010, 06:25
Display posts from previous: Sort by

The useful life of a certain piece of equipment is

  Question banks Downloads My Bookmarks Reviews  
Print view
First unread post

Moderators: Bunuel, VeritasPrepKarishma

Search for:


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

Powered by phpBB © phpBB Group and phpBB SEO

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®.

Main navigation

GMAT Resources

Partners

MBA Resources

www.gmac.com|www.mba.com