Louis C. K. was born on September 12, 1967.

Louis C. K. was born on September 12, 1967.

The answer depends on if you can choose the same kind of donuts more then once. Or in other words, is repetition permitted.

If you can only choose the same kind of donuts only once, it is a 21 choose 12 problem:

C(n,k) = n! / (k! (n - k)!)

C(21, 12) = 21! / (12! (21 - 12)!)

= 21! / (12! (9)!)

= 293,930

If you can choose the same kind of donuts more then once, it is a combination with repetition problem.

P(n+k-1,k) = (n+k-1)! / (k! (n-1)!)

or put it into C(n,k) with n+k-1 as 21 + 12 - 1 = 32 and k as 12 so

C(21+12-1,12)

= C(32, 12)

= 32! / (12! (32 - 12)!)

= 32! / (12! (20)!)

= 225,792,840

12 deg C = 261.15 K

Composed by Mozart.