Let X = the time between two successive arrivals at the drive-up window of a local bank. If X has an exponential distribution with λ = 1, (which is identical to a standard gamma distribution with α = 1), compute the following. (If necessary, round your answer to three decimal places.)

(a) The expected time between two successive arrivals
(b) The standard deviation of the time between successive arrivals
(c) P(X ? 1)
(d) P(2 ? X ? 5)

Astudent found the solution below for the given inequality. |x-9|< -4 x-9> 4 and x-9< -4 x> 13 and x< 5 which of the following explains whether the student is correct? -the student is completely correct because the student correctly wrote and solved the compound inequality. -the student is partially correct because only one part of the compound inequality is written correctly. -the student is partially correct because the student should have written the statements using “or” instead of “and.” -the student is completely incorrect because there is no solution to this inequality.