请教 大全-TEST 1-17

17.   In the past year, there has been a large drop in the number of new cars sold, due to harsh economic conditions in the marketplace and high taxes. At the same time, the average price paid for a new car has risen dramatically.

Which of the following, if true, best explains the increase in the average price of a new car?

(A) The price of used cars has climbed steadily over the past ten years.

(B) There will be a tax reduction later in the year which is expected to aid moderate and low income families.

(C) The market for expensive car has been unaffected by the current economic conditions.

(D) Economic conditions are expected to get significantly worse before the end of the year.（C）

(E) Low demand for trucks and vans has led to lower production in the factories.

答案是C ，但是 has been unaffected by the current economic conditions 如何解释INCREASE IN THE PRICE ？

一个比方

一般来说，一辆BMW或者benz的seden大概在$50k 左右，一辆honda seden大概在18k左右

如果一个dealer 卖出4辆车，2辆 benz,2辆honda,那么车的average price就是(50*2+18*2)/4=136/4=34

那么现在经济不景气，按照C的解释豪华车没收影响，主要受影响的是经济型的车。那么假设同样这个dealer现在只买出了3两车，豪华车没受经济影响，还是买出了2辆，经济型车受影响了，只买出了一辆。那么现在的车的average price就是(50*2+18)/3=118/3=39.3

这样average price就increase了。