【分享一道极品题的解剖过程】Surveys in Domorica indicate that only 10 percent of D...

babychubear

这是一道2012prep里的加强题，但是其求解思路算是比较少见，网上看了关于此题各方神圣的解答，还是不能解出心中疑惑，思考半小时后，终于有解，现将思考成果po出来，供大家鉴赏，求轻拍~

Surveys in Domorica indicate that only 10percent of Domoricans in their twenties read a newspaper regularly, while more than half of all Domoricans over thirty read a newspaperregularly. AlthoughDomoricans in their twentiesconstitute a large proportion of the population, newspaper publishers nonetheless predict that ten years from now, the percentage of Domoricans who regularlyread a newspaperwill probably be no lower than it is today.

Whichof the following, if true, provides the strongest grounds for thenewspaper publishers’ prediction?

A.      Thenumber of Domoricans intheir twenties is less than the number of Domoricans over thirty.

B.      The number of newspapers in Domoricahas been gradually increasing over the past several decades.

C.      The proportion of Domoricans in their twentieswho regularly read a newspaper has always been low.

D.     The surveys defined a regularreader of a newspaper as someonewho reads a newspapermore than twice a week.

E.      The proportion of Domoricans who regularlyread a newspaperwas higher 20 years ago than it is today.

OA:C   

注：答案选中可见

• 基本知识：
  全国读书比例是一个加权平均数；每代人群的人数=权数；每代人群中的读书比例=每项平均对象
  

• 思想：这道题用到的思想类似数学题中的分析法，即：要使什么成立，就要使什么成立，进而什么成立…，这样一步一步追溯，最终追溯到源头的第一个premise
  

• 难度分析：我们都知道，最有效的加强方式就是找到原题中argument所缺失的假设，填补那个gap，但是这个题缺失的假设就是第一个最基础最开端的假设，因此，只有沿着一条线逆推；而以往的题gap大都出在中间，可以同时从两边顺逆双向推导，更容易找到那个缺失的假设。
  

• 理顺后的逻辑链：
  

   Premise: 20岁的人读书比例一直很低-->现在那些读书比例较高的30岁以上的那代人在10年前，即他们20多岁时读书比例也很低==同一代人，20岁时读书比例 低，但是到了30岁以后 读书比例就会自动变高 + 现在20岁人群很多==>

  Conclusion:10年以后，他们变成了30岁人群，且读书比例会增加了，且又人数众多，权数大，自然更有可能拉动读书比例的平均数

skipp

顶楼主！