Permutation questions- urgent help needed

2200andbeyondXD
Thu, 24 Jan 2013 18:32:28 +0000

@pckeller,
i just found all the possibilties then subtracted those that can’t be from those…

@drsteve,
By the way, i did do the taking for different variables thing (before you said the hint actually) and i did see the pattern and all that…
and that’s why I asked you in the first place if u were sure they can be expressed by j and k… because i can’t put the pattern into a nPr or nCr expression…
I guess what i couldn’t do from the beginning was
“and the second is by actually thinking about what you’re counting (again, I think some examples might be necessary to realize this)”

the 2nd part…