Question

Julie has two formal events to go to -- one for her work and one for her partner's work. She has six formal dresses -- two blue ones, one black, one red, and two white. Since the same people will not be at the two events she is okay wearing the same dress. She wants to find the probability that she wears one black and one white dress. Given the two events are independent, what is the probability?

Answer 1

If the dresses are chosen at random a probability tree can be constructed showing the probabilities of the various combinations that are possible. It shows the total probability of choosing a black, then white, or a white, then black dress is 1/9.