in a zoo there are 2 wolfs 2 tigers 2 lions 2 sheep we need to house them in four cages (two animals in each cage) by these rules: A.in one cage we need to house a wolf and a sheep. B.we cant house two animals of the same kind in one cage. which one of these arguments in necessarily true: 1.at least in one cage a lion and a tiger will be housed. 2.at exactly one cage a lion and a sheep will be housed. 3.at exactly one cage a tiger and a sheep will be housed. 4.there is another cage in which a sheep and a wolf will be housed. what is the simplest way to solve this question?? i found one combination for each argument and tried to find common stuff between them. regarding answer 1: |wolf ,sheep |lion,tiger|sheep,lion|wolf,tiger| regarding answer 2: |wolf,sheep |sheep,lion|wolf ,tiger|lion,tiger| regarding answer 3: |wolf,sheep |sheep,tiger|wolf ,lion|lion,tiger| regarding answer 4: if we put a fifth cage it leaves us with 4 animals we cant put two animals in each one of the four left cages if we left with only fours animals,so its not possible. i found that a lion and a tiger in one cage is the common thing among these three combinations. but i cant think of three combination in order to solve this kind of question it takes too much time. is there any easier way??