May 4, 2009

Problem of the Week

for Monday, May 4, 2009

(Proposed by Micaela P., Grade 2)

The game of Set is played with a deck of cards, each card showing a number (either one, two, or three) of shapes (oval, squiggle, or diamond) in one of three colors (red, green, or purple) and shadings (solid, striped, or empty). There is exactly one card for each possibility. Three cards form a Set if they are either all the same or all different with respect to each of the four qualities (number, shape, color, and shading). Three cards are chosen at random from a shuffled deck. What is the probability that they form a Set?

May 4th solution