72. A bridge hand in which there is no card higher than a 9 is called a Yarborough after the Earl who liked to bet at 1000 to 1 that your bridge hand would have a card that was 10 or higher. What is the probability of a Yarborough when you draw 13 cards out of a deck of 52?

81. A town has four TV repairmen. In the first week of September four TV sets break and their owners call repairmen chosen at random. Find the probability that the number of repairmen who have jobs is 1, 2, 3, 4.

85. If we get five cards then the probability of a flush is 0.001981. The goal of this problem is to calculate the probability of a flush in seven card stud. We begin by noting that

C52,7 =133,484,560

For 5 k 7, let pk be the probability we get exactly k cards of one suit when we draw 7 from a deck of 52. Find p5, p6, p7. Then find the answer to our question p5 + p6 + p7.