A password for a computer consists of 10 characters. The first character is a non zero digit, the next four characters are non repeating letters in the English alphabet (which consists of 26 letters), and the last five characters are non zero integers which are selected with replacement. How many possible computer passwords of this type exist? If it took you were able to attempt 20 many possible computer passwords of this type exist? If it took you were able to attempt 20 passwords per minute, how long would it take you to exhaust all the possible passwords? Explain please

Question

anonymous · Answer

9 x 26 x 25 x 24 x 23 x 9 x 9 x 9 x 9

anonymous · Answer

How did you get that?

anonymous · Answer

you have 9 choices for the first character. 1 through 9 (discounting 0)
you have 26 choices for the first letter
you have 25 choices for the next letter because you took up one letter for the firt letter already. 
similarly you have 24 and 23 choices for the next two letters.
for the next 4 digits you have 9 choices for each of them