Ok so I can regard my multiset of "rooks" as being a set m={4*b,2*r,2*e} like you stated and use this theorem in my book that states:
For n rooks of k colors the number or arrangements is equal to
n!(n!/(the repetition number of each object)!).
So the number of arrangements would be...
Homework Statement
How many ways can two red and four blue rooks be placed on an 8-by-8 chessboard so that no two rooks can attack one another.
Homework Equations
1)Number of permutations with two types=(n choose n1)=n!/((n1!)(n-n11))
2)Number of ways to place n rooks which have k...