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题库 / Prep2012-CR-12
The faster a car is traveling, the less time the driver has to avoid a potential accident, and if a car does crash, higher speeds increase the risk of a fatality. Between 1995 and 2000, average highway speeds increased significantly in the United States, yet, over that time, there was a drop in the number of car-crash fatalities per highway mile driven by cars.
Which of the following, if true about the United States between 1995 and 2000, most helps to explain why the fatality rate decreased in spite of the increase in average highway speeds?
The average number of passengers per car on highways increased.
There were increases in both the proportion of people who wore seat belts and the proportion of cars that were equipped with airbags as safety devices.
The increase in average highway speeds occurred as legal speed limits were raised on one highway after another.
The average mileage driven on highways per car increased.
In most locations on the highways, the density of vehicles on the highway did not decrease, although individual vehicles, on average, made their trips more quickly.
1、fatality死者 每公里死者变少--死亡率下降 和miles数无关，所以专注解释死亡率就好
For why D is wrong, it may be explained as: there is a certain number of fatalities per highway mile driven say 0.01. It doesn't matter how many miles were driven exactly. This only implies that if 100 miles were driven, there was one fatality. If 1000 miles were driven, there were 10 fatalities. If 10000 miles were driven, there were 100 fatalities. The fact that people have started driving more does not increase/reduce this number. (credit to gmatclub forum)
E是did not decrease (same or increase), 不是did not increase
只看问题就OK了
车速增加 ➡️ 致死率减少
background：车子行驶速度越快，死亡率越高。
1995-2000之间高速公路的平均速度显著增加了，但是高速每公里的死亡人数下降了。问explain, 即找一个新的evidence抵消因为速度增加带来的死亡率增加
choice b, 佩戴安全带的乘客，和配置了安全气囊的汽车比例增加了。correct
类比推理。
不过这题CQ没意义。。地球人都会第一时间想到系了安全带的原因
For why D is wrong, it may be explained as: there is a certain number of fatalities per highway mile driven say 0.01. It doesn't matter how many miles were driven exactly. This only implies that if 100 miles were driven, there was one fatality. If 1000 miles were driven, there were 10 fatalities. If 10000 miles were driven, there were 100 fatalities. The fact that people have started driving more does not increase/reduce this number. (credit to gmatclub forum)
原来：开的越快越容易发生事故，发生事故的致死率就越高。
现在：速度提高很多，致死率却下降。
解释：虽然速度快即使发生了事故也不容易致死
致死率VS.事故率
E为什么不对呢。。。
A. More passengers per car would likely mean even more fatalities per highway mile driven, since more people
would die per car accident.
B. Correct. More seatbelts and airbags would have probably reduced the average number of fatalities per car
accident, resulting in fewer fatalities per mile driven even if the higher speeds resulted in more car accidents.
感觉是相关因果
选项c有点迷惑，但我还是选了B，想问老师，是不是c只是解释了前提：即average highway speed increased singnaficantly.
因果推理。
不对。。。因果。。。
类比