NEW HERE? LEARN MORE
closeclose
Last visit was: 23 Apr 2024, 19:47 It is currently 23 Apr 2024, 19:47
Decision Tracker
My Rewards
New posts
New comers' posts

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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

A large cube 10cm on a side is composed of smaller cubes 1

User avatar
kripalkavi
Director
Director
Joined: 21 Mar 2006
Posts: 639
Own Kudos [?]: 134 [0]
Given Kudos: 0
Location: Bangalore
Send PM
A large cube 10cm on a side is composed of smaller cubes 1 [#permalink] New post   18 Nov 2006, 19:11
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

100% (01:05) correct 0% (00:00) wrong based on 1 sessions
Hide Show timer Statistics
A large cube 10cm on a side is composed of smaller cubes 1 cm on a side. The large cube is
printed red on its outside surfaces and then all the cubes are mixed in a drum.
If one cube is selected randomly, which of the following is the approximate probability
that the cube will have at least one red face?

A) 1:6
B) 1:5
C) 1:4
D) 1:3
E) 1:2



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Data Sufficiency (DS) Forum
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
User avatar
anindyat
Manager
Manager
Joined: 08 Jun 2006
Posts: 160
Own Kudos [?]: 214 [0]
Given Kudos: 0
Location: Washington DC
Send PM
Re: A large cube 10cm on a side is composed of smaller cubes 1 [#permalink] New post   18 Nov 2006, 20:00
Is it 1 : 2

Explanation
Total smaller cubes = 10^3
Number of inner cubes, which are not painted = (10 – 2)^3
So probability 10^3 – 8^3 : 10^3 => 488 : 1000 = 1 : 2 (approx)
User avatar
tennis1ball
Director
Director
Joined: 25 Jun 2006
Posts: 651
Own Kudos [?]: 930 [0]
Given Kudos: 0
Send PM
Re: A large cube 10cm on a side is composed of smaller cubes 1 [#permalink] New post   19 Nov 2006, 00:16
agree with E.

the painted are 488 out of total 1000.
User avatar
jamesrwright3
Manager
Manager
Joined: 08 May 2004
Posts: 135
Own Kudos [?]: 2 [0]
Given Kudos: 0
Location: Pittsburgh
Send PM
Re: A large cube 10cm on a side is composed of smaller cubes 1 [#permalink] New post   19 Nov 2006, 00:56
Quick question
Here you said

Quote:
Total smaller cubes = 10^3


I don't think there are a 1000 cubes inside of this cube?
Or are you talking about total area?
The above equation is for volume which is not relevant, we are looking for surface area right?
User avatar
tennis1ball
Director
Director
Joined: 25 Jun 2006
Posts: 651
Own Kudos [?]: 930 [0]
Given Kudos: 0
Send PM
Re: A large cube 10cm on a side is composed of smaller cubes 1 [#permalink] New post   19 Nov 2006, 03:26
It is not surface area, nor is it volume.

you need to count the no of small cubes.
User avatar
kripalkavi
Director
Director
Joined: 21 Mar 2006
Posts: 639
Own Kudos [?]: 134 [0]
Given Kudos: 0
Location: Bangalore
Send PM
Re: A large cube 10cm on a side is composed of smaller cubes 1 [#permalink] New post   19 Nov 2006, 21:01
anindyat wrote:
Is it 1 : 2

Explanation
Total smaller cubes = 10^3
Number of inner cubes, which are not painted = (10 – 2)^3
So probability 10^3 – 8^3 : 10^3 => 488 : 1000 = 1 : 2 (approx)


Can you please tell me how you arrived at that? Totally lost :?
User avatar
kripalkavi
Director
Director
Joined: 21 Mar 2006
Posts: 639
Own Kudos [?]: 134 [0]
Given Kudos: 0
Location: Bangalore
Send PM
Re: A large cube 10cm on a side is composed of smaller cubes 1 [#permalink] New post   19 Nov 2006, 21:04
anindyat wrote:
Is it 1 : 2

Explanation
Total smaller cubes = 10^3
Number of inner cubes, which are not painted = (10 – 2)^3
So probability 10^3 – 8^3 : 10^3 => 488 : 1000 = 1 : 2 (approx)


Can you please tell me how you arrived at that? Totally lost :?
User avatar
Juaz
Manager
Manager
Joined: 18 Jul 2006
Posts: 243
Own Kudos [?]: 271 [0]
Given Kudos: 0
Send PM
Re: A large cube 10cm on a side is composed of smaller cubes 1 [#permalink] New post   20 Nov 2006, 00:24
kripalkavi wrote:
anindyat wrote:
Is it 1 : 2

Explanation
Total smaller cubes = 10^3
Number of inner cubes, which are not painted = (10 – 2)^3
So probability 10^3 – 8^3 : 10^3 => 488 : 1000 = 1 : 2 (approx)


Can you please tell me how you arrived at that? Totally lost :?

In simple terms, there is 8x8x8 cube inside 10x10x10 which remains unpainted (as top and bottom i.e. 1st and 10th cubes are painted)
User avatar
kripalkavi
Director
Director
Joined: 21 Mar 2006
Posts: 639
Own Kudos [?]: 134 [0]
Given Kudos: 0
Location: Bangalore
Send PM
Re: A large cube 10cm on a side is composed of smaller cubes 1 [#permalink] New post   20 Nov 2006, 01:16
Juaz wrote:
kripalkavi wrote:
anindyat wrote:
Is it 1 : 2

Explanation
Total smaller cubes = 10^3
Number of inner cubes, which are not painted = (10 – 2)^3
So probability 10^3 – 8^3 : 10^3 => 488 : 1000 = 1 : 2 (approx)


Can you please tell me how you arrived at that? Totally lost :?

In simple terms, there is 8x8x8 cube inside 10x10x10 which remains unpainted (as top and bottom i.e. 1st and 10th cubes are painted)

Thanks! As youy might have guessed, OA is E



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Data Sufficiency (DS) Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
GMAT Club Bot
gmatclubot
Re: A large cube 10cm on a side is composed of smaller cubes 1 [#permalink]
20 Nov 2006, 01:16
Moderators:
Bunuel
Math Expert
92883 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3137 posts
GMATBusters
GMAT Tutor
1907 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions