Someone shot 10 arrows at a target with 10 concentric rings, each being worth a different integer number of points from 1 to 10. How many different ways are there of scoring 10 points by doing this? (Note that not all the arrows have to hit the target and that order matters; 6 first then 4 is different from 4 first then 6. Also note that two or more arrows may hit the same ring.)
(In reply to
re(4): Intuitive Representation IMHO by nikki)
Oh, I meant that in my solution, I proved the formula. You used it without proving it because you already knew the formula. It doesn't need to be proven if you already know it, but the proof is for people like me who don't know that formula already.