Target Test Prep 20% Off Flash Sale is on! Code: FLASH20

Redeem
Target Test Prep
5-Day Free Trial
5-day free, full-access trial TTP

Available with Beat the GMAT members only code

MORE DETAILS
Target Test Prep
Magoosh
Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

MORE DETAILS
Magoosh

napkin ring

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Junior | Next Rank: 30 Posts
Posts: 20
Joined: Mon Jul 07, 2008 7:05 am
Location: Back of Beyond

napkin ring

by ousek » Mon Jul 27, 2009 2:45 pm
Hey, GMAT beaters...

Here is a riddle you could find in the GMAT:

I made a cylindrical hole in a perfect sphere with an electric drill, and took out the two extremities of the sphere to get a nice napkin ring. Mum is very happy!

Image

Cut, my napkin ring is now 6cm high.

:arrow: What is its volume ?

The answer after your explanations ! :wink:

Enjoy !

Ousek
Fucking GMAT
Top
Newbie | Next Rank: 10 Posts
Posts: 8
Joined: Thu Jul 16, 2009 1:20 am
Location: Berlin

by ASS1991 » Mon Jul 27, 2009 5:55 pm
Nice question, but don't we need the radius/diameter or any other information?
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 157
Joined: Tue Oct 07, 2008 5:47 am
Thanked: 3 times

by PussInBoots » Mon Jul 27, 2009 8:30 pm
Your mom won't be proud of your low GMAT score because this is very dumb question...
Top
User avatar
Junior | Next Rank: 30 Posts
Posts: 20
Joined: Mon Jul 07, 2008 7:05 am
Location: Back of Beyond

by ousek » Fri Jul 31, 2009 2:30 pm
ASS1991 wrote:Nice question, but don't we need the radius/diameter or any other information?
No, there is no further information available !
Nevertheless, one can find the answer... :wink:
PussInBoots wrote:Your mom won't be proud of your low GMAT score because this is very dumb question...
A dumb question, yes, perhaps! But I wonder why you don't answer, in this case! :lol: I guess you should try an answer...

:arrow: Come on guys, let's think about it...
Fucking GMAT
Top
Newbie | Next Rank: 10 Posts
Posts: 3
Joined: Fri Jul 31, 2009 1:57 pm

by nestlepurelife » Fri Jul 31, 2009 4:09 pm
https://en.wikipedia.org/wiki/Napkin_ring_problem

I doubt it will be on the GMAT. However, for the curious, I've linked the idea behind this problem.
Top
User avatar
Junior | Next Rank: 30 Posts
Posts: 20
Joined: Mon Jul 07, 2008 7:05 am
Location: Back of Beyond

by ousek » Fri Jul 31, 2009 4:48 pm
Neither do I.
As far as I am concerned, I solved this problem in few minutes, even if I didn't have the knowledge explained in your link (thank you for it). Nevertheless, no question should require "few minutes".

I just posted it because I believe it make people search... and the more a brain works, the faster it goes!
Plus, I believe same of you here would have enjoyed such a riddle...
Fucking GMAT
Top
Legendary Member
Posts: 752
Joined: Sun May 17, 2009 11:04 pm
Location: Tokyo
Thanked: 81 times
GMAT Score:680

by tohellandback » Fri Jul 31, 2009 4:56 pm
Is it 36pi? and I have a very very simple solution.

Just imagine that the length you cut is almost equal to 0. In that case the diameter of the sphere will be 6
and the volume of the sphere is 4/3 * pi* 3^3 =36pi

of course it took me more than 5 minutes to figure out this solution.

and IMO it might not not be on GMAT or a question like this..but it is certainly not a "dumb" question
The powers of two are bloody impolite!!
Top
User avatar
Junior | Next Rank: 30 Posts
Posts: 20
Joined: Mon Jul 07, 2008 7:05 am
Location: Back of Beyond

by ousek » Sat Aug 01, 2009 2:22 pm
:lol: tohellandback, you got it !

This is exactly the way one should solve the problem. The other way being, of course, to write three pages of calculus...
Fucking GMAT
Top
Post new topic Post Reply
• Page 1 of 1