Alice and Bob are supposed to meet in the cafeteria. Alicearrives at a random time between
noon and 1pm, and wait for 15 minutes upon her arrival and thenleaves. Bob also also arrives
at a random time between noon and 1 pm, but waits up to 20 minutesand then leaves.
(a) What is the probability that Bob arrives before 12:20?
(b) What is the probability that Alice and Bob meet?
(c) If Bob arrives later than Alice, what is the probability thatthey meet?
(d) Suppose that Alice and Bob have managed to meet. What is theprobability that Bob
has arrived before 12:20?
