4.57 The Birthday Problem, continued If n people enter a room, find these probabilities: A: None of the people have the same birthday B: At least two of the people have the same birthday Solve for

a. n=3

b. n=4 (NOTE: Surprisingly, P(B) increases rapidly as n increases. For example, for n = 20, P(B)=0.411; for n=40, P(B)=0.891.)