----- Original Message ---- From: David Gale <gale@math.berkeley.edu> To: math-fun <math-fun@mailman.xmission.com> Sent: Thursday, August 9, 2007 3:17:48 AM Subject: RE: [math-fun] How we "do mathematics" ...

A (very) old one I like :

Two Death Valley marathonians friends complete their run together and seek shadow in their tent nearby the finish line.

The first one had prepared a fresh 5-liter tank of water in a cooling box and his friend a similar 3-liter one.

They were about to start drinking when a journalist enters the tent desperately asking for water.

OK, the water is divided into three equal parts -- and drunk.

The thankful journalist insists to pay his share and leaves 8 dollars to be split between the two friends.

How?

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Why is this problem so fascinating? The two friends are paid $8. The guy who contributed 5 l gets $5, and the guy who contributed 3 l gets $3. Or maybe the $8 goes towards paying for their campsite. I must be missing something. Here's another solution. I like this one better. The guy who contributed 5 l drinks 8/3 l, so he sold 7/3 l. The guy who contributed 3 l drinks 8/3 l, so he sold 1/3 l. So the money should be distributed $7 and $1. Either way, this problem is suitable for a kindergarten entrance exam. Gene ____________________________________________________________________________________ Pinpoint customers who are looking for what you sell. http://searchmarketing.yahoo.com/ _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun ____________________________________________________________________________________ Choose the right car based on your needs. Check out Yahoo! Autos new Car Finder tool. http://autos.yahoo.com/carfinder/