Question

How many ways are there to choose a valid password of the computer system

Answer 1

A standard Qwerty keyboard can (by default) produce 96 unique characters.

Suppose we intend to create a password of size 'n'.

These each of the n places of this password can be filled using any of the above mentioned 96 characters.

Thus, total possible combinations would be $=96*96*96*....*96=96^n$

Thus, there are $96^n$ ways to choose a valid password (of size 'n') for the computer system.