Question

How many four letter permutations can be formed from the first five letters of the alphabet?

Answer 1

Answer:   120

Step-by-step explanation:

Permutation means that order matters.

$_nP_r = \dfrac{n!}{(n-r)!}\quad \text{where n is the total \# of items and r is the quantity chosen} \\\\\text{In the given problem, n = 5 and r = 4}\\\\\\_5P_4=\dfrac{5!}{(5-4)!} = \dfrac{5\times 4\times 3\times 2 \times 1}{1}=120$