71Sir, That page has still three unsolved problems.
Q) Find the no. of three elements sets of positive integers ( a,b,c ) such that a*b*c = 2310.
Q) Find the no. of integers between 1 and 10000 with at least one 8 and at least one 9 as digits.
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6 Answers
341@ninepointcircle - 231 is not a prime :D
post #11 at http://www.targetiit.com/iit-jee-forum/posts/combinatorics-18476.html
1sry
i didnt saw it
the nit has to be solved by stirling number concept ..u can see it on wiki
the answer will be 1+ S(5,2)+S(5,3) = 41
71Well, I can give some hints of course you try it out:
First 1 digit nos: Not possible
2 digit Nos.: 89,98 so 2 numbers
3 digit No: 2* 3!2!
and so on.. only upto 4 digits.. think
