Question 377540
Probability of 10:00 and 10:24 = 24/60 = .4 mean waiting time 24/2 = 12 min
Probability of 10:24 and 11:00 = 36/60 = .6 mean waiting time 36/2 = 18 min
Expected waiting time = .4*12 + .6*18 = 15.6 min (sum of the individual expectations)
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Ed