Consider an unsorted array of n distinct integers, in the range 1,…, 3n. all permutations of any n out of the 3n numbers are equally likely. given a value x in the range 1,…, 3n, a linear search is used to determine the index of x in the array, or that it is not there. give an expression for the expected number of comparisons made, as a function of n. justify your answer.