4. a. Describe how to use index cards to conduct one run of a simulation of this situation: Boxes of Cheerios once randomly contained one of three magic tricks. call them A, B, and C. Pat wants magic trick B. If Pat buys two boxes. what is the probability that Pat does get magic trick B? b. Draw a tree diagram to illustrate the question in part a. What is the probability that Pat gets magic trick B if she buys two boxes