Hi i need some guidance with these questions.
1. How many numbers greater than 4000 can be formed from the figures 3, 5, 7, 8, 9? (Repetitions are not allowed).
2. If 6Pr = 120 find the value of r.
6!/(6-r)! = 120 ; is there a way to expand the (6-r)! ?
3. Show that nPr = (n-2)Pr + 2r...