Register FAQ / Rules Forum Spy Search Today's Posts Mark Forums Read
Go Back   MacRumors Forums > Mac Community > Community Discussion

Reply
 
Thread Tools Search this Thread Display Modes
Old Feb 9, 2008, 12:45 AM   #26
CalBoy
macrumors 601
 
CalBoy's Avatar
 
Join Date: May 2007
Quote:
Originally Posted by Doctor Q View Post
A bookshelf has three encyclopedia volumes: A-I, J-R, and S-Z. They are in the usual order, left to right on the shelf. The covers are 1/16" thick. Each book has pages numbered 1 to 1000. Each sheet of paper is 1/250 of an inch thick.

If a bookworm chews its way from page 1 of the A-I volume through page 1000 of the S-Z volume, how far did it travel?

(You may decide whether or not the bookworm ate the starting page and the ending page; use whichever assumption makes your computation easier.)
Quote:
Originally Posted by swiftaw View Post
6.25 inches
I got this as well, but something about this whole thing makes me think that Doctor Q is going to do something clever and show us how wrong we are.
CalBoy is offline   0 Reply With Quote
Old Feb 9, 2008, 06:53 AM   #27
creator2456
macrumors 68000
 
creator2456's Avatar
 
Join Date: Jul 2007
Location: Chicago
Quote:
Originally Posted by swiftaw View Post
6.25 inches
((500pages x 3books) x .004") + (4covers x .0625") = 6.25"


(7girls x 2legs) + (7girls x 7backpacks x 7big cats x 4legs) + (7girls x 7backpacks x 7big cats x 7small cats x 4legs) = 10990legs
__________________
I have stuff...but I am also lazy.
Buy some of my stuff!!!

Last edited by creator2456; Feb 9, 2008 at 07:01 AM. Reason: added legs problem
creator2456 is offline   0 Reply With Quote
Old Feb 9, 2008, 07:53 AM   #28
Zwhaler
macrumors 603
 
Zwhaler's Avatar
 
Join Date: Jun 2006
Quote:
Originally Posted by dobbin View Post
I don't see why this is at all hard. It seems very simple to me.

7 girls --> 14 legs
7x7 = 49 backpacks
49x7 = 343 big cats --> 1372 legs
343x7 = 2401 little cats --> 9604 legs
14+1372+9604 = 10990 legs in total
I did the exact same thing. Got it on my first try Im cool
__________________
2x2.93 24GB 25TB 2x1TB 840EVO 2x UAD OCTO, Apollo, 4-710d
Check Out My YouTube Channel~~~~~~~~~~~~~~~~~~~
Zwhaler is offline   0 Reply With Quote
Old Feb 9, 2008, 08:07 AM   #29
yippy
macrumors 68020
 
yippy's Avatar
 
Join Date: Mar 2004
Location: Oak Park, IL
Send a message via AIM to yippy
Doh!, you guys are right, you only need 500 pieces of paper to get 1000 pages.

In that case the answer is 6.25"
yippy is offline   0 Reply With Quote
Old Feb 9, 2008, 11:54 AM   #30
SilentPanda
Moderator emeritus
 
SilentPanda's Avatar
 
Join Date: Oct 2002
Location: The Bamboo Forest
There could be 501 pages per book if, after opening the cover you see that the first page facing you is blank, flipping that you see pages 1 and 2, then 3 and 4, until you get to the end which has 999 and 1000. Flipping 1000 would leave a blank side of the page. Which would be 501 pages per book. They might do that in order to not have the ink rub off from page 1 or 1000 onto the harder outside of the book. Poor little inch worm would have to inch 3/250ths further!

__________________
My 24 hour web cam! ʕノᴥʔノ ︵ ┻━┻
SilentPanda is offline   0 Reply With Quote
Old Feb 9, 2008, 12:52 PM   #31
jsw
Moderator emeritus
 
jsw's Avatar
 
Join Date: Mar 2004
Location: Andover, MA
Explanation (highlight to see):
The books (square brackets indicate covers):
[A-I][J-R][S-Z]
The amount chewed through:
][J-R][
Why? Because the first page of A-I is to the right on the shelf, and the last page of S-Z is to the left.

So four covers plus, as has adequately been explained, 500 pages.

4x(1/16) + 500x(1/250) = 4/16 + 500/250 = 1/4 + 2 = 2.25".

As per Nermal. I just felt it was time to explain.
__________________
You'll be the one moaning for me to give you some. - THC(taken out of context)

Last edited by jsw; Feb 9, 2008 at 02:39 PM. Reason: No ruining of the fun....
jsw is offline   0 Reply With Quote
Old Feb 9, 2008, 01:54 PM   #32
Nermal
Moderator
 
Nermal's Avatar
 
Join Date: Dec 2002
Location: Whakatane, New Zealand
I was kind of hoping Q would come along and say "Nermal's right, now figure out why" but you had to go and ruin that, didn't you?
Nermal is offline   0 Reply With Quote
Old Feb 9, 2008, 02:27 PM   #33
CalBoy
macrumors 601
 
CalBoy's Avatar
 
Join Date: May 2007
Quote:
Originally Posted by jsw View Post
As per Nermal. I just felt it was time to explain.
I knew I wasn't right for some reason.

Quote:
Originally Posted by CalBoy View Post
I got this as well, but something about this whole thing makes me think that Doctor Q is going to do something clever and show us how wrong we are.
You ruined the prophecy jsw! Only Doctor Q was to show us the way!
CalBoy is offline   0 Reply With Quote
Old Feb 9, 2008, 02:36 PM   #34
skyrider007
macrumors 65816
 
skyrider007's Avatar
 
Join Date: Aug 2007
Location: Bangkok
this is fun!
__________________
15.4" MacBook Pro 2.0GHz i7 iPad 3G iPod Touch 16GB (2G)
BlackBerry Bold 9780 (white)
skyrider007 is offline   0 Reply With Quote
Old Feb 9, 2008, 02:39 PM   #35
aquajet
macrumors 68020
 
Join Date: Feb 2005
Location: DFW
Quote:
Originally Posted by jsw View Post
Why? Because the first page of A-I is to the right on the shelf, and the last page of S-Z is to the left.
To be fair, Dr. Q said the volumes were "in the usual order, left to right". He didn't say anything about whether or not any of the volumes were shelved upside down.
aquajet is offline   0 Reply With Quote
Old Feb 9, 2008, 02:40 PM   #36
jsw
Moderator emeritus
 
jsw's Avatar
 
Join Date: Mar 2004
Location: Andover, MA
Quote:
Originally Posted by Nermal View Post
I was kind of hoping Q would come along and say "Nermal's right, now figure out why" but you had to go and ruin that, didn't you?
Fine, fine, I white-texted it.

I just wanted your brilliance to be proven correct.
Quote:
Originally Posted by CalBoy View Post
You ruined the prophecy jsw! Only Doctor Q was to show us the way!
You assume we're different people, now, don't you?
Quote:
Originally Posted by aquajet View Post
To be fair, Dr. Q said the volumes were "in the usual order, left to right". He didn't say anything about whether or not any of the volumes were shelved upside down.
You make a good point - they might also have been laid flat, in which case we'd need the width and/or height of the paper as well as information about the binding, which wasn't provided.
__________________
You'll be the one moaning for me to give you some. - THC(taken out of context)
jsw is offline   0 Reply With Quote
Old Feb 9, 2008, 03:01 PM   #37
Doctor Q
Administrator
 
Doctor Q's Avatar
 
Join Date: Sep 2002
Location: Ruler factory
I was waiting for someone to post the correct answer AND an explanation. Nermal was first with the answer, jsw with the explanation.

The cute friendly bookworm says thanks for the snack.
__________________
Does size matter?
Doctor Q is offline   0 Reply With Quote
Old Feb 9, 2008, 03:37 PM   #38
fridgeymonster3
macrumors 6502
 
Join Date: Jan 2008
I got the answer on my first try. It was pretty easy; however, I don't think we should be bragging it was easy since it is for 5th graders. I mean, come on, post something challenging!
__________________
"Even in my sleep-deprived state, I've managed to pull off another one of my classic pranks. BAZINGA!"
fridgeymonster3 is offline   0 Reply With Quote
Old Feb 9, 2008, 03:41 PM   #39
CalBoy
macrumors 601
 
CalBoy's Avatar
 
Join Date: May 2007
Quote:
Originally Posted by fridgeymonster3 View Post
I mean, come on, post something challenging!
Ok, since you asked.

There are 3 doors. Behind 1 door lies immense wealth and riches. Behind the other two lie certain death.

A guard asks you to choose a door and you pick #2. The guard then reveals to you what's behind Door #1 and you see that behind it was one of two chances of certain death.

The guard now asks you if you would like to change your selection from Door #2 to Door #3.

Mathematically is there a probability increase that benefits you if you change doors?

BTW, I don't know the answer to this, but I've seen it thrown around a few times
CalBoy is offline   0 Reply With Quote
Old Feb 9, 2008, 03:41 PM   #40
jsw
Moderator emeritus
 
jsw's Avatar
 
Join Date: Mar 2004
Location: Andover, MA
Quote:
Originally Posted by fridgeymonster3 View Post
I got the answer on my first try. It was pretty easy; however, I don't think we should be bragging it was easy since it is for 5th graders. I mean, come on, post something challenging!
Pick any of these and report back with the answer!
__________________
You'll be the one moaning for me to give you some. - THC(taken out of context)
jsw is offline   0 Reply With Quote
Old Feb 9, 2008, 03:45 PM   #41
WildCowboy
Administrator/Editor
 
WildCowboy's Avatar
 
Join Date: Jan 2005
Quote:
Originally Posted by CalBoy View Post
Mathematically is there a probability increase that benefits you if you change doors?
Yes, very much so.
__________________
Editor in Chief, MacRumors
WildCowboy is offline   0 Reply With Quote
Old Feb 9, 2008, 03:46 PM   #42
CalBoy
macrumors 601
 
CalBoy's Avatar
 
Join Date: May 2007
Quote:
Originally Posted by WildCowboy View Post
Darn it! You weren't supposed to say anything!
CalBoy is offline   0 Reply With Quote
Old Feb 9, 2008, 03:47 PM   #43
jsw
Moderator emeritus
 
jsw's Avatar
 
Join Date: Mar 2004
Location: Andover, MA
Quote:
Originally Posted by CalBoy View Post
Mathematically is there a probability increase that benefits you if you change doors?
Yes!

Edit: damn it! Darned kids forcing me to make them fruit smoothies and slowing down my response time. Grrr. In a few months, though, I shall prevail!
__________________
You'll be the one moaning for me to give you some. - THC(taken out of context)
jsw is offline   0 Reply With Quote
Old Feb 9, 2008, 03:48 PM   #44
WildCowboy
Administrator/Editor
 
WildCowboy's Avatar
 
Join Date: Jan 2005
Quote:
Originally Posted by jsw View Post
Stop copying off of my paper!
__________________
Editor in Chief, MacRumors
WildCowboy is offline   0 Reply With Quote
Old Feb 9, 2008, 03:52 PM   #45
Doctor Q
Administrator
 
Doctor Q's Avatar
 
Join Date: Sep 2002
Location: Ruler factory
Can you prove which is larger, e^pi or pi^e, using properties of those numbers rather than simply computing the exponentials?

It's a real question, not a trick. I had this problem on a test. If only I could remember the answer!
__________________
Does size matter?
Doctor Q is offline   0 Reply With Quote
Old Feb 9, 2008, 03:52 PM   #46
kosmo
macrumors newbie
 
Join Date: Apr 2002
Location: Atlanta
Quote:
Originally Posted by CalBoy View Post
Ok, since you asked.

There are 3 doors. Behind 1 door lies immense wealth and riches. Behind the other two lie certain death.

A guard asks you to choose a door and you pick #2. The guard then reveals to you what's behind Door #1 and you see that behind it was one of two chances of certain death.

The guard now asks you if you would like to change your selection from Door #2 to Door #3.

Mathematically is there a probability increase that benefits you if you change doors?

BTW, I don't know the answer to this, but I've seen it thrown around a few times
Yes, your odds are increased by changing doors as "odd" as that seems. The first time you select a door you have a 1/3 chance of picking the right door and a 2/3 chance of picking the wrong door. After a wrong door has been revealed to you, the door you picked still has a 1/3 chance of being right however the other door now has a 2/3 chance of being right. Change doors!
kosmo is offline   0 Reply With Quote
Old Feb 9, 2008, 03:57 PM   #47
fridgeymonster3
macrumors 6502
 
Join Date: Jan 2008
Monty Hall problem...real creative . Now if one of us explained that in a simple format without links to wikipedia (or borrowing any of their descriptions/examples) that would be much more impressive. My father taught statistics & probability at a graduate school and explained it in very simple terms before wikipedia existed which made it easy (not that me the psychology major, law school student could understand ).

Quote:
Originally Posted by jsw View Post
Pick any of these and report back with the answer!
sure i'll solve those and get back to you.....in say, when some else figures them out, I pounce on their answers, and post them here first
__________________
"Even in my sleep-deprived state, I've managed to pull off another one of my classic pranks. BAZINGA!"

Last edited by WildCowboy; Feb 9, 2008 at 03:59 PM. Reason: post merge
fridgeymonster3 is offline   0 Reply With Quote
Old Feb 9, 2008, 04:01 PM   #48
WildCowboy
Administrator/Editor
 
WildCowboy's Avatar
 
Join Date: Jan 2005
Quote:
Originally Posted by fridgeymonster3 View Post
Now if one of us explained that in a simple format without links to wikipedia (or borrowing any of their descriptions/examples) that would be much more impressive.
What, you're looking for real effort out of us?!

Why reinvent the wheel when Wikipedia already has a good, thorough explanation?
__________________
Editor in Chief, MacRumors
WildCowboy is offline   0 Reply With Quote
Old Feb 9, 2008, 04:07 PM   #49
EricNau
Moderator
 
EricNau's Avatar
 
Join Date: Apr 2005
Location: San Francisco, CA
I love this one:
Give the next two numbers in this sequence:

9, 10, 11, 12, 13, 14, 21, ...
EricNau is offline   0 Reply With Quote
Old Feb 9, 2008, 04:08 PM   #50
jsw
Moderator emeritus
 
jsw's Avatar
 
Join Date: Mar 2004
Location: Andover, MA
Quote:
Originally Posted by Doctor Q View Post
Can you prove which is larger, epi or pie?
This is quite easy to do visually with no math.

Epi:
Click image for larger version

Name:	EpiPenDemo-770152.jpg
Views:	21
Size:	71.1 KB
ID:	101851

Pie:
Click image for larger version

Name:	Pie-Lady.jpg
Views:	9
Size:	24.3 KB
ID:	101852

I think the visual cues allow it to be easily shown that the Epi is much smaller than a typical pie.
__________________
You'll be the one moaning for me to give you some. - THC(taken out of context)
jsw is offline   0 Reply With Quote


Reply
MacRumors Forums > Mac Community > Community Discussion

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Similar Threads
thread Thread Starter Forum Replies Last Post
Tricky problem for expert on iMovie for iPad allamb iPad Apps 2 Sep 11, 2012 06:55 AM
3rd Grade Math: Summer Review Splash Math App klkatielong iPad Apps 0 Jul 18, 2012 12:56 PM
[Math App] Homework teaches kids math and reports to parents Gaea deBomb iPhone and iPod touch Apps 0 Jul 3, 2012 04:35 AM
A Middle and High School Math App: Cool Math mathfantasia iPad Apps 2 Jun 19, 2012 06:35 PM
5+7+10+5+2+3= ? Math Aloud ! true mental math ... left & right brain. mobile.esd.mx iPhone and iPod touch Apps 0 Jun 1, 2012 04:17 PM

Forum Jump

All times are GMT -5. The time now is 02:26 AM.

Mac Rumors | Mac | iPhone | iPhone Game Reviews | iPhone Apps

Mobile Version | Fixed | Fluid | Fluid HD
Copyright 2002-2013, MacRumors.com, LLC