Box with three cards

From VMT

Contents 1 The Problem 2 Why is this a problem? 3 Solutions 3.1 Strategy: "drawing balls from a jar" 3.2 Strategy: "complementary problem"

[edit] The Problem

A box contains three cards. One card is red on both sides, one card is green on both sides, and one card is red on one side and green on the other. One card is selected from the box at random, and the color on one side is observed. If this side is green, what is the probability that the other side of the card is also green?

[edit] Why is this a problem?

[edit] Solutions

Lets list here different ways from which one can approach this problem.

[edit] Strategy: "drawing balls from a jar"

[edit] Strategy: "complementary problem"