shrive555 wrote:
A popular website requires users to create a password consisting of digits only. If no digit may be repeated and each password must be at least 9 digits long, how many passwords are possible?
A. 9! + 10!
B. 2 x 10!
C. 9! x 10!
D. 19!
E. 20!
A. 9! + 10!
B. 2 x 10!
C. 9! x 10!
D. 19!
E. 20!
The number of ways to create a 10-digit password from 10 digits is 10P10 = 10!.
Thus, the number of ways to create the codes is 10! + 10! = 2(10!).
Answer: B