Posted by **matt** on Sunday, April 13, 2008 at 8:45pm.

Your password for a given website is made up of three letters followed by

four numbers. Find the number of possible passwords if there are no

restrictions on what three letters and what four numbers can be used.

- maths permutation and combination - answer pls check -
**matt**, Sunday, April 13, 2008 at 9:06pm
Pls check if my answer is correct

26C3*10C4

=26!/(26-3)!3! . 10!/(10-4)!4!

= 26*25*24*23!/23!*6 . 10*9*8*7*6!/6!*4*3*2*1

=15600/6 * 5040/24

=2600*210

=546000

- maths permutation and combination -
**bobpursley**, Sunday, April 13, 2008 at 9:38pm
I didn't see that letters or numbers cant be used more than once.

26*26*26*26*10*10*10*10

As I read it AAAA0000 is allowed, your number didn't include those.

- maths permutation and combination -
**matt**, Sunday, April 13, 2008 at 9:44pm
Thanks

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