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This is a Grouping: Partially Defined, Numerical Distribution game.
The game scenario indicates that there are two cages and one exhibition for ten birds. At least two birds and at most four birds are on exhibition, and there are at most four birds in each of two cages:
This leads to some easy distributions, such as a 4-4-2 (cage-cage-exhibit) or 4-2-4 and 2-4-4, etc. However, the distributions do not play a major role in this game. Instead, it is the grouping rules and the restrictions between all of the birds that answers the questions.
These are the ten birds:
The second rule states that birds that are both of the same sex and of the same kind cannot be caged together. Therefore, only one male parakeet can be assigned to each cage. Since there are three male parakeets and only two cages, it follows that at least one male parakeet must always be exhibited, along with a corresponding female parakeet. Thus, one of Q, R, or S and one of T or W is always on exhibit.
So, at least one pair of parakeets must always be exhibited. However, one of the initial rules states that at most two pairs of birds can be exhibited at a time. Therefore, a pair of goldfinches and a pair of lovebirds can never be exhibited together. This inference is tested directly in question #17.
The second rule states that two birds of the same sex and kind cannot be caged together. Thus, J and K (two female goldfinches) cannot be caged together. Same for Q and R (two male parakeets), Q and S (two male parakeets), R and S (two male parakeets), and T and W (two female parakeets). These inferences can be diagrammed as:
While the cage inferences are all based on the second rule, there is more variation in the exhibit inferences.
First, from the third rule, S cannot be exhibited with J or W:
Of course, if S cannot be exhibited with W, then we can infer that S must be exhibited with T, the only other female parakeet:
The next few inferences derive from the stipulation that pairs of one male and one female of the same type must be exhibited. Because S can only be exhibited with T, and not with W, neither Q nor R can be exhibited with S:
Again, this occurs because Q or R would require W, and S cannot be exhibited with W.
Another inference in that same vein involves J and K, the two female goldfinches. J and K can never be exhibited together, because there is only one male goldfinch, and for both J and K to be exhibited, there would have to be two male goldfinches:
The final inference on the exhibition list reflects the inference discussed above that goldfinches and lovebirds cannot be exhibited together.
Combining all of the above rules and inferences leads to the following:
With this information in hand, we are ready to attack the questions.