Problem Solver

[Guest]

Make three cards of equal size. Label both sides of one card with the letter A, both sides of the second with the letter B, and one side of the third with letter A and the other side with letter B. Select a card at random, and place it on a table. There will be either an A or a B facing up. What is the probability that the letter facing down on this card is differnt from the letter facing up? :roll:

 

[stapel]

See if this article on Wikipedia is helpful. It also has some links at the bottom to related articles.

Eliz.

P.S. to tutors: The article in the link above covers the posted exercise (though using colors for the two sides of the cards, rather than letters). The article explains the basic foundation, gives two different approaches, provides the solution, and lists related sites.

However, the poster has complained vigorously (in private messages) that this information was not at all helpful. She might appreciate further information and/or explanation, the stuff of which I do not feel qualified to provide, especially since she has not provided any information on which part of the solution she still doesn't "get". Thank you.