书是 Kaplan LSAT Premier 2010-2011, Page 98-99. 题目是选自Prep Test 3, Section 1, Game 3, Question 19
At an automobile exhibition, cars are displayed on each floor of a three-floor building. One each floor, the cars are either all family cars or all sports cars, either all new or all used, and either all production models or all research models. The following conditions apply to this exhibition: 1. If the exhibition includs both family cars and sports cars, then each family car is displayed on a lower numbered floor than any sports car. 2. The exhibition includs no used research models 3. The exhibition includs no research models that are sports cars. 4. There are new cars on floor 1 5. There are used cars on floor 3
Q11: If all the production models in the exhibition are used, then which one of the following statments must be true? (A) There are family cars on floor 1 (B) There are new cars on floor 2 (C) There are research models on floor 2 (D) There are family cars on floor 3 (E) There are sports cars on floor 3
正确答案是 (A) 我的答案是(E)
以下是解析里的解释: If all production models are used, then a car that is not used (new), must not be production (research). So floor 1's new cars must be of the research variety, which means that floor 1's cars must also be family cars (Rules 3). We get this in choice (A). (B) through (E) could all be true, but also could be false.
我的问题在于, 正确答案里的推论是: ( production = used) -> ( new = research ) + ( floor 1 = new ) -> ( floor 1 = research )+ ( no sport research model ) -> (floor 1 = family)
但是同样的, Rule 1 告诉我们, family 展出的层数一定低于sport. 所以车展有3层, 可能出现family的是1,2层, 可能出现sport的是2,3层. 那么, ( no sport research model )+ ( floor 3 = used ) = ( floor 3 = used product sport ) 厄, 这样, (E)应该同样是正确的啊作者: taoransk 时间: 2010-8-29 21:45
-.- 打字那么久结果自己发现问题了 ... 有可能出现3层都是家庭或体育车的情况, 然后这题小前提pass掉了3层都是体育车的假设, 所以1楼是家庭车是一定的. 但是3楼是体育车只是可能 ....