IBM Research | Ponder This | March 2003 challenges
Skip to main content

Ponder This

March 2003

<<February March April>>

Ponder This Challenge:

This month's puzzle was supplied by Vladimir Sedach.

We have 100 meters of fencing, which we use to enclose a pasture. Our fence must begin and end at the oak tree. Ground south of the oak tree, or less than 20 meters north of the oak tree, is worth $100 per square meter; but ground more than 20 meters north of the oak tree is worth $200 per square meter.

What shape maximizes the total value of the enclosed pasture, and what is this value?

The "oak tree" is a single point. "20 meters north" refers to an east-west line passing 20 meters north of the tree. "Begin and end at the oak tree" means that both ends of the fence touch this point. All of this takes place on a flat Earth.

We will post the names of those who submit a correct, original solution! If you don't want your name posted then please include such a statement in your submission!

We invite visitors to our website to submit an elegant solution. Send your submission to the

If you have any problems you think we might enjoy, please send them in. All replies should be sent to:


Challenge: 03/03/2003 @ 10:00 AM EST
Solution: 03/03/2003 @ 10:00 AM EST
List Updated: 03/03/2003 @ 10:00 AM EST

People who answered correctly:

Stephane Peysson (03.04.2003@12:46:39PM EST)

Michael Brand (03.04.2003@01:41:00PM EST)
Michael Swart (03.04.2003@04:27:17PM EST)
Jayavel Sounderpandian (03.06.2003@06:01:01PM EST)
Hagen von Eitzen (03.08.2003@11:24:34AM EST)
Steve Horvath (03.10.2003@09:05:29AM EST)
John G. Fletcher (03.10.2003@03:55:13PM EST)
Chris Shannon (03.10.2003@05:26:00PM EST)
Alex Proudfoot (03.13.2003@06:53:42PM EST)
Aditya Utturwar (03.17.2003@11:21:19AM EST)
Rainer Rosenthal (03.17.2003@05:42:29PM EST)
Morgan Sherman (03.19.2003@08:07:24PM EST)
Sebastian Casalaina-Martin (03.19.2003@08:07:24PM EST)
Maxim G. Smith (03.20.2003@02:59:47PM EST)
Rocke Verser (03.21.2003@05:59:27AM EST)
Andreas Knappe (03.21.2003@07:39:39AM EST)
Bob Stewart (03.21.2003@11:50:09AM EST)
Florbela Duarte (03.21.2003@06:51:06PM EST)
Gyozo Nagy (03.23.2003@04:19:25PM EST)
Donald T. Dodson (03.25.2003@09:44:10AM EST)
Nachiket Bapat (03.28.2003@06:06:30PM EST)
Amos Guler (03.30.2003@02:29:21AM EST)
Troels Nørgaard (03.31.2003@06:21:42AM EST)
Nis Jorgensen (03.31.2003@11:42:39AM EST)

Attention: If your name is posted here and you wish it removed please send email to the