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

Step-by-step 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 :-

$^{26}P_5=\frac{26!}{(26-5)!}\\\\=\frac{26\times25\times24\times23\times22\times21!}{21!}\\\\=26\times25\times24\times23\times22=7893600$

Hence, there area 7893600 passwords are possible.