Stormy Weather

stormy weather puzzle - 1

Stephen Barr observes that a pitched roof receives less rain per unit area than level ground does. This seems to mean that rain that falls at a slant will be less wetting than rain that falls vertically. Why isn’t this so?

Click for Answer

Horse Sense

horse sense puzzle

From the U.K. Schools Mathematical Challenge, a multiple-choice competition for students ages 11-14:

Humphrey the horse at full stretch is hard to match. But that is just what you have to do: move one match to make another horse just like (i.e. congruent to) Humphrey. Which match must you move?

Click for Answer

Catbird Seat

catbird seat 1

A ladder is leaning against a tree. On the center rung is a pussycat. She must be a very determined pussycat, because she remains on that rung as we draw the foot of the ladder away from the tree until the ladder is lying flat on the ground. What path does the pussycat describe as she undergoes this indignity?

Click for Answer

Cut and Thrust

barbeau paper cutting puzzle - 1

University of Toronto math professor Ed Barbeau can take a rectangular piece of paper and, using only a pair of scissors, produce the object pictured above. How?

Click for Answer

Sound Sense

http://books.google.com/books?id=VAevYgEACAAJ&d

Here is a class of a dozen boys, who, being called up to give their names were photographed by the instantaneous process just as each one was commencing to pronounce his own name. The twelve names were Oom, Alden, Eastman, Alfred, Arthur, Luke, Fletcher, Matthew, Theodore, Richard, Shirmer, and Hisswald. Now it would not seem possible to be able to give the correct name to each of the twelve boys, but if you practice the list over to each one, you will find it not a difficult task to locate the proper name for every one of the boys.

Click for Answer

Four Puzzles

  1. You’re playing bridge. Each of four players is dealt 13 cards. You and your partner find that between you you hold all 13 cards of one suit. Is this more or less likely than that the two of you hold no cards of one suit?
  2. As he left a restaurant, a man gave the cashier a card bearing the number 102004180. The cashier charged him nothing. Why?
  3. How can you position a marble on the floor of an empty room so that I can’t hit it with a baseball?
  4. Thrice what number is twice that number?
Click for Answer