Question

In how many ways can you arrange 3 out of 5 books (a, b, c, d, and

e.on a shelf, if the order of each arrangement matters (so abc is different from cba)?

Answer 1

yes bro...
the easiest way is to use 5C3
= 5! /(5-3)!3!
= 5(5-1)(5-2)(5-3)!/ (5-3)!3!
= 5×4×3×2/3×2
= 5×4 = 20ways