Question

12. Computer system #1 requires logon passwords to be eight upper-case letters. How many different passwords are there for system #1? Computer system #2 requires logon passwords to be eight characters, which may be upper or lower-case letters, the numbers 0 through 9, and the characters $, #, and %. How many different passwords are there for system #2?

Answer 1

12. Computer system #1 requires logon passwords to be eight upper-case letters. How many different passwords are there for system #1?

Answer:------------- According to given condition in question, we have 8 places and 26 letters (A..........Z) to be filled at those places.
So, we have 26 choices to put at every place because we can repeat a letter as many times .
So, Total number of different password will be,
===>26x26x26x26x26x26x26x26
===> 26⁸
===> 208,827,064,576

Computer system #2 requires logon passwords to be eight characters, which may be upper or lower-case letters, the numbers 0 through 9, and the characters $, #, and %. How many different passwords are there for system #2?

Answer:------------- According to given condition in question, we have 8 places and 65 choices (A..........Z and a............z and 0..........9 and $, #, %​​​​​​​ ) to be filled at those places.
So, we have 65 choices to put at every place because we can repeat a letter as many times .
So, Total number of different password will be,
===>65x65x65x65x65x65x65x65
===> 65⁸
===> 318,644,812,890,625