Welcome to BrainDen.com - Brain Teasers Forum

 Welcome to BrainDen.com - Brain Teasers Forum. Like most online communities you must register to post in our community, but don't worry this is a simple free process. To be a part of BrainDen Forums you may create a new account or sign in if you already have an account. As a member you could start new topics, reply to others, subscribe to topics/forums to get automatic updates, get your own profile and make new friends. Of course, you can also enjoy our collection of amazing optical illusions and cool math games. If you like our site, you may support us by simply clicking Google "+1" or Facebook "Like" buttons at the top. If you have a website, we would appreciate a little link to BrainDen. Thanks and enjoy the Den :-)
Guest Message by DevFuse

LOTR Telephone

Best Answer DeGe, 23 October 2013 - 10:10 AM

Spoiler for slightly better

Spoiler for Optimising Kukupai's solution for M
Go to the full post

8 replies to this topic

Senior Member

• Members
• 1837 posts
• Gender:Female

Posted 18 October 2013 - 04:26 PM

**Risking the chastisement of repeating another forum question**

Samwise Gamgee has a square plot of land, each side being 1 unit. One day, Sam finds out that the dark Lord Sauron has a telephone line that he uses to speak with a traitor amongst the hobbits.

Gandalf informs him that the telephone line runs in a straight line parallel to the ground and passes beneath the square plot of land, but he does not know its location. Sam decides to dig up around the perimeter of his land to discover the telephone line, but Gandalf says it is not necessary to dig around the entire length of 4 units.

Sam brightens up, and says "I know what you mean. I can just dig 3 sides and still discover it. For even if the phone line runs along the fourth side, I will still detect it at the end points ! "

Gandalf shakes his head. "No, Sam. You are on the right track, but you can do better than that."

What solution does Gandalf have in mind for the optimum length of the "digging curve" ?

• 0

#2 DeGe

DeGe

• Members
• 132 posts
• Gender:Male
• Location:Paris

Posted 18 October 2013 - 05:16 PM

Spoiler for Possibility

• 0

#3 dgreening

dgreening

Junior Member

• Members
• 98 posts
• Gender:Male
• Location:Maryland [DC area]

Posted 18 October 2013 - 05:22 PM

Spoiler for One approach

• 0

#4 dgreening

dgreening

Junior Member

• Members
• 98 posts
• Gender:Male
• Location:Maryland [DC area]

Posted 18 October 2013 - 05:23 PM

Spoiler for Possibility

I agree, we were working in parallel.

• 0

#5 DeGe

DeGe

• Members
• 132 posts
• Gender:Male
• Location:Paris

Posted 21 October 2013 - 08:31 AM

Spoiler for Better than before

Edited by DeGe, 21 October 2013 - 08:32 AM.

• 0

Senior Member

• Members
• 1837 posts
• Gender:Female

Posted 21 October 2013 - 11:02 PM

Should we be digging the inside of the shape?

• 0

#7 kukupai

kukupai

Junior Member

• Members
• 30 posts
• Gender:Female

Posted 23 October 2013 - 12:08 AM

Spoiler for slightly better

• 0

#8 DeGe

DeGe

• Members
• 132 posts
• Gender:Male
• Location:Paris

Posted 23 October 2013 - 10:10 AM   Best Answer

Spoiler for slightly better

Spoiler for Optimising Kukupai's solution for M

• 0

#9 dgreening

dgreening

Junior Member

• Members
• 98 posts
• Gender:Male
• Location:Maryland [DC area]

Posted 24 October 2013 - 09:13 PM

Spoiler for slightly better

Spoiler for Optimising Kukupai's solution for M

very elegant solution(s)! My hat is off to both of you!

• 0

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users