a - A pair of dice is thrown 11 times. What is the probabiliy that the eleven possible values of their sum are obtained once each (this can be solved by simple probability theory).
b - if the pair of dice is thrown 12 times, what is the probability that the eleven possible values of their sum are obtained at least once each
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.