请教一道逻辑题

michellelong

    In the United States, vacationers account for more than half of all visitors to what are technically called"pure aquariums" but for fewer than one quarter of all visitors to zoos, which usually include a "zoo aquarium" of relarively modest scope.

    Which of the following, if true, most helps to account for the difference described above between visitors to zoos and visitors to pure aquariums?

(B) Virtually all large metropolitan areas have zoos,whereas only a few large metropolitan areas have pure aquariums.

(C) Over the last ten years, newly constructed pure have outnumbered newly established zoos by a factor of two to one.

(D) People who visit a zoo in a given year are two times more likely to visit a pure aquarium that year than are people who do not visit a zoo.

(E) The zoo aquariums of zoos that are in the same city as a pure aquarium tend to be smaller than the aquariums of zoos that have no pure aquarium nearby.

答案是B,请教为什么?

arundhati

这题曾讨论过。

题干说：度假者占所有去水族馆的游客的一半以上，但占所有去动物园的游客的不到四分之一。

这是个数学问题，同样的人数，占这个集合的一半，却占那个集合的四分之一，那么原因就是前者的基数小，而后者的基数大。

正如B所说：几乎所有的大城市有zoos，而少数有水族馆。（意思就是zoos比较多，那么游客的基数自然多，而水族馆少，那么游客数量就较少。）

michellelong

谢谢，我还听到另外一种解释：vacationor一词指的是外地到本地来的度假者．因为水族馆只有少数城市有，所以水族馆里的外地度假者就相对多一些．不过我还是觉得你的解释更合理．