Question 618887: Can someone tell me if I am doing this correctly?
The Question: On a certain computer system, passwords consist of any four letters or digits (0,1,2,3,4,5,6,7,8,9). Letters and digits cannot be repeated in a password. How many passwords are possible?
What I have done:
(10)(9)(8)(7)=5,040
(26)(25)(24)(23)=358,800
5,040*358,800= 1,808,352,000
Could that possible be correct?? If not, what am I missing? THANK YOU!!!!
Answer by Edwin McCravy(20054)   (Show Source):
You can put this solution on YOUR website!
I interpret this as though passwords can have both digits and letters mixed.
For instance not only can you have passwords like 4703 and HGLP, but also
passwords like these A5H2 and 7J6K, with mixed letters and digits.
Therefore, we can use any of 36 characters
(26 letters plus 10 digits = 36 characters)
(36)(35)(34)(33) = 1,413,720
Edwin
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