1. Communication: The rack behind a coat-check counter collapses and 20 coats slip off their numbered hangers. When the first person comes to retrieve one of these coats, the clerk brings them out and holds them up one at a time for the customer to identify.
a) what is the probability that the clerk will find the customer's coat
i) on the first try? I got 1/20
ii) on the second try? 1/20
iii) on the third try? 1/20
iv) in fewer than 10 tries? 9 x 1/20
b) What is the expected number of coats the clerk will have to bring our before finding the customer's coat?
the answer is 95 but i have no clue how they got that
c) Explain why you cannot use a geometric distribution to calculate the waiting time.
i said because the events aren't independent
a) what is the probability that the clerk will find the customer's coat
i) on the first try? I got 1/20
ii) on the second try? 1/20
iii) on the third try? 1/20
iv) in fewer than 10 tries? 9 x 1/20
b) What is the expected number of coats the clerk will have to bring our before finding the customer's coat?
the answer is 95 but i have no clue how they got that
c) Explain why you cannot use a geometric distribution to calculate the waiting time.
i said because the events aren't independent