Question

To generate a phone bill, observe the duration of the call in integer minutes (rounding up). Charge for m 1,2,3,.. minutes if the exact duration t is m-1< tS m. Let Bm denote the event that a call is billed for m minutes. The probability of each event Bm is Pl Bal-a(1-a)m-1 where -I-(0.69) 1/3 О.116. (a) Classify a call as long (L) if the call lasts more than three minutes, then PLL]691 (b) What is the probability that a call will be billed for nine minutes or less? Answer: 78 Hint: The probabilities P[Bm] are terms in a geometric series. Remember that when Irl < 1, 1-

Answer 1