Competition for Rubistov

Do you like Ruby on Rails? Show yourself in the competition from Ciklum and win a free pass to the RubyConfUa 2010 conference !

Conference => sharing experience with like-minded colleagues => saving time on learning new products.

Conditions:

Create and send us a utility (link to the code, the code itself), until October 10 inclusive, to the address ror@ciklum.net. In the letter, specify the name, city, contact details (except mail).

Criteria for evaluation:

• Performance
• Code quality, documentation (comments)
• Tests

On October 12, Ciklum will respond to all participants and announce the 3 winners on its website dedicated to the IT Community.
The RubyConfUa 2010 conference takes place in Kiev on October 16 - 17. If you wish, you can visit only one day.
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The task:

Write a utility that would calculate the probability of obtaining the number K when throwing N M-sided dice.

The utility should take three arguments in the following order:
0) K - the number, the probability of which is calculated;
1) N - the number of thrown bones;
2) M is the number of faces at each bone.

The utility should return only the calculated value as a FLOAT.