Question

How many ways can a librarian arrange 15 books on a top shelf if she has 20 books from which to pick?

Answer 1

Use the permutation formula
nPr = (n!)/((n-r)!)
20P15 = (20!)/((20-15)!)
20P15 = (20!)/(5!)

The final answer is choice A

Answer 2

The correct answer is A turned this in got a 100 hoped this helped ya.