Answer:
7,893,600
Step-by-step explanation:
Permutations
n = possible things used (26 letters)
r = how many at a time (5 at a time - this is without repeating)
nPr = n! / (n - r)!
26P5 = 26! / (26 - 5)!
26! = 26 x 25 x 24 x 23 x 22... = 403291461126605635584000000
(26 - 5)! = 21! = 51090942171709440000
An easy hack for solving division of large factorials is to use canceling.
26!/21! = 26 x 25 x 24 x 23 x 22 (because 21 down to 1 is cancelled by 21!)
= 7,893,600
