The number of distinguishable permutations, P, of n objects where p objects are alike q objects are alike, r objects are alike, and so on is

a. P(n,r) = n! / (p-q)!
b. P(n,r) = n! / p! q! r!
c. P(n,r) = n! / p+q+r
d. P(n,r) = n! / p-q-r





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