Question

Can someone please answer. There is one problem. There's a picture. Thank you!

Answer 1

The answer is B, 1,365.

The combination formula nCr=n!(n−r)!(r!)

n is the number of elements (total).

r is the number of elements picked from the set.

In this case, n = 15 and r = 4

15!(11!)(4!)

=1365

So, there are 1365 ways of listening to the CD's.

Hope I helped!