some friends and i were talking about how many possiblities there were for a 6 digid password if you're allowed to use the letters a-z and the numbers 0-9. I know there is a general algorithm but can't remember it.
2007-01-13 19:19:10 · 7 answers · asked by Eric A 1 in Science & Mathematics ➔ Mathematics
there is a formula for it , u use permutations , i think its n!/(n-r)!
"!" is factorial ex. 4!= 4*3*2*1 in yur case n would be 26+10 = 36 and r would be 6
2007-01-13 19:23:37 · answer #1 · answered by emperor_ham 2 · 0⤊ 0⤋
Andrew is correct, it is 36^6. The password can reuse digits, so the password could be, for example, "bbbbbb". The choice to use the letter "b" as the first character in the password does not restrict in any way the number of options available for the letters that follow. So there are 36 possibilites for each character.
If, on the other hand, we were playing some game in which characters could not be reused (perhaps we've created 36 tiles, one with each character on it, and are constructing our password from those tiles), then the answer would be 36*35*34*33*32*31, because with each character chosen, we have one fewer option from which to choose the next character. We are not playing such a game, though, so this is not the answer.
2007-01-13 19:46:49 · answer #2 · answered by Hal 2 · 0⤊ 0⤋
Let x be the number of values that each digit can have
Let n be the number of digits in the password,
Then there are x^n possible passwords.
So there are 36^6 possible 6-digit passwords using (a-z, 0-9)
That's 2176782336.
2007-01-13 19:30:27 · answer #3 · answered by Andrew 6 · 0⤊ 0⤋
(36^6)-1
thirty six raised to the sixth minus one. You can't have a blank pass word. Subtract (36^5) to remove passwords less than 6 characters
2116316159 combinations which at 1 second per try would take you 67 years to try each one
2007-01-13 19:43:02 · answer #4 · answered by nullgateway 2 · 0⤊ 0⤋
Every password I've seen has had to start with an alpha character. Therefore the total possibilities are
26*36^5 = 1,572,120,576
2007-01-13 20:20:20 · answer #5 · answered by Helmut 7 · 0⤊ 0⤋
If you can repeat them then it would be
36 to the sixth power.
If you can't repeat then it would be
36 x 35 x34 x 33x 32 x 31
2007-01-13 19:23:46 · answer #6 · answered by alwaysmoose 7 · 1⤊ 0⤋
(all letters + #s)^(n - 1)
therefore, 36 to 5th power
2007-01-13 19:26:58 · answer #7 · answered by ? 2 · 0⤊ 0⤋