Let s be a set of n numbers. let x be the set of all subsets of s of size k, and let y be the set of all ordered k-tuples (s1, s2, , sk) such that s1 < s2 < < sk. that is, x = {{s1, s2, , sk} | si is in s and all si's are distinct}, and y = {(s1, s2, , sk) | si is in s and s1 < s2 < < sk}. (a) define a one-to-one correspondence f : x → y. explain why f is one-to-one and onto.

(b) determine |x| and |y|.

|x| =

|y| =

can someone answer part b of this question. the answer available is incorrect and unclear.