5 . Two methods, A and B, are available for teaching a certain industrial skill. There is an 80% chance of successfully learning the skill if method A is used, and a 95% chance of success if method B is used. However, method B is substantially more expensive and is therefore used only 25% of the time (method A is used the other 75% of the time). The following notations are suggested: A-Method A is used. B-Method B is used. . L-The skill was learned successfully. a) What is the probability that a randomly chosen worker will learn the skill successfully? (Hint: ist write out each probability in probability notation including the question. 2nd draw a probability tree. 3"d use the Law of Total Probability.) b) A worker learned the skill successfully. What is the probability that he was taught by method A? (Hint: 1st write out the question in probability notation. 2nd use Bayes Rule.)