You are trying to locate an old high school friend who lives in Chicago. Unfortunately, your friend's name is Anthony Smith and the Chicago phone book lists phone numbers for 24 diff erent people named Anthony Smith.
a) If you call 10 of these Anthony Smith's at random, what is the probability that you will call your friend? (Assume that your friend's phone number is listed in the phone book, and that you don't call anybody twice.)
b) Let X be the number of calls you need to make until you find your friend. Give the probability massfunction for X.
c) How many calls do you expect to make until you find your friend? (Again, assume that your friend's phone number is listed in the phone book, and that you don't call anybody twice.)