Question

A computer password uses 5 letters where no letter may be repeated. How many passwords are possible?

Answer 1

The correct answer is 26!/21!. I have turned this in and gotten a 100. Hoped this helped ya .

Answer 2

Answer: 7893600

Explanation:

Given: The number of digits used for computer password = 5

Number of letter in English alphabet=26

By using permutations, the required number of passwordssuch that there is no letter repeated is given by :-

`^(26)P_5=(26!)/((26-5)!)\\\\=(26*25*24*23*22*21!)/(21!)\\\\=26*25*24*23*22=7893600`

Hence, there area 7893600 passwords are possible.