Question

How many possible password of length four to eight symbols can be formed using English alphabets both upper and lower case (A-Z and a-z), decimal (0-9) and the special characters(_ and $) ?

Answer 1

In a password, symbol/characters can be repeated. first calculate the total

symbols which can be used in a password.

So there are total 26(A-Z),26(a-z),10(0-9) and 2(_,$) symbols.

that is equal to 26+26+10+2=64.

Total number of password of length 4:

here at each place can filled in total number of symbols i.e 64 way for each

place.Then total number of possible password is:

64*64*64*64=16777216

Total number of password of length 5:

here at each place can filled in total number of symbols i.e 64 way for each

place.Then total number of possible password is:

64*64*64*64*64=1073741824

Similarly,

Total number of password of length 6:

64*64*64*64*64*64=68719476736

Total number of password of length 7:

64*64*64*64*64*64*64=4398046511104

Total number of password of length 8:

64*64*64*64*64*64*64=281474976710656

Hence the total number of password possible is:285,942,833,217,536