It is currently 11 Dec 2017, 21:51

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

geometry_cube

  post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Director
Director
avatar
Joined: 22 Aug 2007
Posts: 566

Kudos [?]: 79 [0], given: 0

geometry_cube [#permalink]

Show Tags

New post 14 Oct 2007, 00:31
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

thanks.
Attachments

Untitled.jpg
Untitled.jpg [ 13.84 KiB | Viewed 760 times ]

Kudos [?]: 79 [0], given: 0

VP
VP
User avatar
Joined: 08 Jun 2005
Posts: 1141

Kudos [?]: 257 [0], given: 0

 [#permalink]

Show Tags

New post 14 Oct 2007, 01:07
You can put 64 1cm cubes into 4cm cube. since 4^3 = 64 and 1^3 = 1.

64/1 = 64

the surface area of 4cm cube is 4^2*6 = 96. the surface area of 1cm cube is 1^2*6 = 6 but we have 64 cubes.

64*6/96 = 4 = 400%

so the answer is (E)

:)

Kudos [?]: 257 [0], given: 0

SVP
SVP
User avatar
Joined: 01 May 2006
Posts: 1794

Kudos [?]: 171 [0], given: 0

 [#permalink]

Show Tags

New post 14 Oct 2007, 01:20
KillerSquirrel wrote:
You can put 64 1cm cubes into 4cm cube. since 4^3 = 64 and 1^3 = 1.

64/1 = 64

the surface area of 4cm cube is 4^2*6 = 96. the surface area of 1cm cube is 1^2*6 = 6 but we have 64 cubes.

64*6/96 = 4 = 400%

so the answer is (E)

:)


I agree on all, except the conclusion.

% Increase = 100 * (New surface - Old surface) / Old Surface = 100 * (64*6 - 96) / 96 = 300 %

So (D) for me :)

Kudos [?]: 171 [0], given: 0

Director
Director
avatar
Joined: 22 Aug 2007
Posts: 566

Kudos [?]: 79 [0], given: 0

Re: geometry_cube [#permalink]

Show Tags

New post 14 Oct 2007, 11:49
Thank you for explanations, KS!

AO is D.

4-1=300% increase

Kudos [?]: 79 [0], given: 0

CEO
CEO
User avatar
Joined: 21 Jan 2007
Posts: 2734

Kudos [?]: 1087 [0], given: 4

Location: New York City
Re: geometry_cube [#permalink]

Show Tags

New post 15 Oct 2007, 12:31
IrinaOK wrote:
Thank you for explanations, KS!

AO is D.

4-1=300% increase


what is the reasoning behind this?

Kudos [?]: 1087 [0], given: 4

Director
Director
avatar
Joined: 22 Aug 2007
Posts: 566

Kudos [?]: 79 [0], given: 0

 [#permalink]

Show Tags

New post 15 Oct 2007, 12:37
KillerSquirrel wrote:
You can put 64 1cm cubes into 4cm cube. since 4^3 = 64 and 1^3 = 1.

64/1 = 64

the surface area of 4cm cube is 4^2*6 = 96. the surface area of 1cm cube is 1^2*6 = 6 but we have 64 cubes.

64*6/96 = 4 = 400%

so the answer is (E)

:)


PLUS to the KS explanation,

(64*6 - 96) / 96 = 4-1 = 3 we are speaking about percentage so multiply by 100%, we get 300 %.

we need to deduct one, cuz the stem is asking percentage increase.

Kudos [?]: 79 [0], given: 0

Director
Director
User avatar
Joined: 31 Mar 2007
Posts: 574

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

Location: Canada eh
 [#permalink]

Show Tags

New post 15 Oct 2007, 16:43
D


remember this when doing this question

sides in a cube = 6

4x4 = 16 per side x 6 = 96 sq cm

now just draw some pictures and you can figure out you can get 64 cubes, each having sides 1 sq cm, times 6 = 6

so new surface area is 384 - 96 = 288 / 96 = 3 x 100% = 300%.

D

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

  [#permalink] 15 Oct 2007, 16:43
Display posts from previous: Sort by

geometry_cube

  post reply Question banks Downloads My Bookmarks Reviews Important topics  

Moderator: chetan2u



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®.