| |
|
|---|
A solution and a new problem is posted every Monday evening during fall and spring semesters at www.cs.colostate.edu/~rmm/mathChallenge
One winner each week is eligible for a free ice cream and topping, courtesy of Cold Stone Creamery.
Email your solutions to solution@math.colostate.edu. Indicate your status (undergrad/grad/faculty/other) and school affiliation or city of residence if you are not affiliated with a school.
Email ideas for future challenges to Ross McConnell (rmm@cs.colostate.edu)
A princess would like to marry the wisest man in the kingdom. There are three obvious candidates, all three of them are unmarried, and all three of them want to marry the princess. Nobody knows which of the three is the wisest, however.
It is well-known that all three of them are good at logic puzzles. Therefore, the princess, who is also very clever, devises a test. She informs the men that she will put them together in a room, blindfold them, and stick one colored star to each of their foreheads. Each star will be red or white, and among the three of them, any combination of red and/or white stars is possible.
When the blindfolds are removed, each contestant is to raise his hand if he sees at least one red star on the other contestants. Whoever can figure out his own star's color should signal this by lowering his hand. The first one to lower his hand will win the contest, but he must be able to name the color of his own star and explain how he knew it. Lucky guessing won't count.
The hero of our story looks around after his blindfold is removed, and sees that the other two contestants each have a red star. He raises his hand, and so do the other two. After a few minutes, he figures out his own star's color, lowers his hand first, and wins the contest.
What color is his star, and how did he know it?
Correct solutions were submitted by
Ian Ellis, Robert Saint-John, Andres Alvares,
Shawn Pocotte (CSU undergrads),
Nathan Behrens (Colorado School of Mines undergrad),
Monica Chawathe, Gabriel Somlo, Daegon Kim, John Brinker, Zhi Zhang,
Priya Venkataraman, Sudip Chakraborty, Jason Connor, Prakash Subramian,
Matt Gibbs, Saravana Sellappa (CSU grad students),
Andrew Johnson (Colorado School of Mines grad student),
Tara LaForce (U.T. Austin grad student),
Javier Tuason, (University of Hawaii grad student),
Nick Krier, Jim Bieman (CSU faculty),
Silvina Diaz (Poudre Schools),
Kevin Garrick (CSU alum),
Rocke Verse (Loveland),
Nicolae Popescu (Fort Collins),
Mike Darschewski (Denver),
Byung-Soo Kim (South Korea),
Julien Gagneur (Heidelberg),
Lou Cairoli (Cleveland),
Kripa Venkatachalam (LSI Logic). Shawn Pocotte wins the ice cream.