Let x denote the amount of time a book on two-hour reserve is actually checked out, and suppose the cdf is the following. f(x) = 0 x < 0 x2 16 0 ≤ x < 4 1 4 ≤ x use the cdf to obtain the following. (if necessary, round your answer to four decimal places.) (a) calculate p(x ≤ 3).