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counting and probability senior
Problem
Rabbits Peter and Pauline have three offspring--Flopsie, Mopsie, and Cotton-tail. These five rabbits are to be distributed to four different pet stores so that no store gets both a parent and a child. It is not required that every store gets a rabbit. In how many different ways can this be done?
(A)
(B)
(C)
(D)
Solution
We tackle the problem by sorting it by how many stores are involved in the transaction. 1) 2 stores are involved. There are ways to choose which of the stores are involved and 2 ways to choose which store recieves the parents. total arrangements. 2) 3 stores are involved. There are ways to choose which of the stores are involved. We then break the problem down to into two subsections - when the parents and grouped together or sold separately. Separately: All children must be in one store. There are ways to arrange this. ways in total. Together: Both parents are in one store and the 3 children are split between the other two. There are ways to split the children and ways to choose to which store each group will be sold. . total arrangements. 3) All 4 stores are involved. We break down the problem as previously shown. Separately: All children must be split between two stores. There are ways to arrange this. We can then arrange which group is sold to which store in ways. . Together: Both parents are in one store and the 3 children are each in another store. There are ways to arrange this. total arrangements. Final Answer: .
Final answer
D