Geraldine is picking a four-digit password by using the digits 0 through 9. She can use each digit only once. How many different passwords are possible

Respuesta :

The answer is 2 because 10/4 = 2.5 and we can't have half of a password.
Number of ways = 10C4 = 10 x 9 x 8 x 7 = 5040

Answer: 5040