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.

Ascientist wants to use a model to present the results of his detailed scientific investigation. why would a model be useful? a )because the model makes the concepts easier to understand b) because the model is easy to put together and to use c) because the model prevents other scientists from asking questions d) because the model requires the audience to pay full attention to it i don't know what to choose because between a and d a is much more likely than d because it only wants to get the attention of the audience. i'm confuse.

Bob is putting books on a shelf and takes a break after filling 18 1/2 inches on the book shelf. the book shelf is now 2/3 full. how long is the entire bookshelf?

One of every 20 customers reports poor customer service on your company’s customer satisfaction survey. you have just created a new process that should cut the number of poor customer service complaints in half. what percentage of customers would you expect to report poor service after this process is implemented? 1.) 5% 2.) 10% 3.) 2% 4.) 2.5%