試題詳解

214. A certain town experiences an average of 5 tornadoes in any four year period. The number of years from now until the town experiences its next tornado as well as the number of years between tornados have identical exponential distributions and all such times are mutually independent

Calculate the median number of years from now until the town experiences its next tornado.
(A) 0.55
(B) 0.73
(C) 0.80
(D) 0.87
(E) 1.25