费费29提的请教

bettyofarim

29. The price of a full-fare coach ticket from Toronto to Dallas on Breezeway Airlines is the same today as it was a year ago, if inflation is taken into account by calculating prices in constant dollars. However, today 90 percent of the Toronto-to-Dallas coach tickets that Breezeway sells are discount tickets and only 10 percent are full-fare tickets, whereas a year ago half were discount tickets and half were full-fare tickets. Therefore, on average, people pay less today in constant dollars for a Breezeway Toronto-to-Dallas coach ticket than they did a year ago.
Which one of the following, if assumed, would allow the conclusion above to be properly drawn?
(A) A Toronto-to-Dallas full-fare coach ticket on Breezeway Airlines provides ticket-holders with a lower level of service today than such a ticket provided a year ago.
(B) A Toronto-to-Dallas discount coach ticket on Breezeway Airlines costs about the same in constant dollars as they did a year ago.
(C) All full-fare coach tickets on Breezeway Airlines cost the same in constant dollars as they did a year ago.
(D) The average number of coach passengers per flight that Breezeway Airlines carries from Toronto to Dallas today is higher than the average number per flight a year ago.
(E) The criteria that Breezeway Airlines uses for permitting passengers to buy discount coach tickets on the Toronto-to-Dallas route are different today than they were a year ago.
答案是B。但是C和B很难区分哦，请NN来分析一下逻辑思路？谢谢先！

深海的小美人鱼

(C) All full-fare coach tickets on Breezeway Airlines cost the same in constant dollars as they did a year ago
涉及与主题无关信息 注意要限定解题范围。文中提到的是The price of a full-fare coach ticket from Toronto to Dallas on Breezeway Airline而不是All full-fare coach tickets on Breezeway Airlines 。所以B更准确地起到桥梁作用。

bettyofarim

哦 ！明白了！谢谢MM

springappleleaf

I am still not sure about this one:

Here are the explanations from

《费费逻辑宝典》详解版

答案选B

本题所讲的，无非就是，people pay less today in constant dollars，而得出这个结论的证据是，以前10%有打折，现在一半有打折，那么，这个前提就是，他们的价格是一样的，不然，如果涨价，就不可能付的少了

A，service，无关

C，full-fare coach tickets cost the same 不等于打折后的也一样

D，无关

E，无关

Is there something wrong about the above yellow highlighted area?  I think it got reversed.  I am pretty confused about the math here.  Can someone explain it futher?  Your help is appreciated in advance.

caterpillar

怎么觉得这个选项不太严谨呢？不涨价但是有可能降价呀？如果现在的discount比原来更便宜，那消费者也付得更少了呀？怎么就得出结论说是the same in constant dollars as they did a year ago.?

清风剑

以下是引用深海的小美人鱼在2003-11-14 3:43:00的发言：
(C) All full-fare coach tickets on Breezeway Airlines cost the same in constant dollars as they did a year ago
涉及与主题无关信息 注意要限定解题范围。文中提到的是The price of a full-fare coach ticket from Toronto to Dallas on Breezeway Airline而不是All full-fare coach tickets on Breezeway Airlines 。所以B更准确地起到桥梁作用。

与美人鱼商榷：

All full-fare coach tickets on Breezeway Airlines 包含a full-fare coach ticket from Toronto to Dallas on Breezeway Airline

可否如下理解此题：

据题意，设价格为P;据B选项，设打折后的价格为Q

则 AVERAGE PAMENT TODAY IS：0.9Q+0.1P    (1)

                A YEAR AGO IS: 0.5Q+0.5P    (2)

(2)-(1) 得 0.4P-0.4Q>0

故，B正确

而C只是扩大范围将原题中的The price of a full-fare coach ticket from Toronto to Dallas on Breezeway Airlines is the same today as it was a year ago重述。

DO YOU THINK SO?

天蝎座1107

这道题想了很久 并不觉得C是扩大范围或者无关 个人的愚见

29. The price of a full-fare coach ticket from Toronto to Dallas on Breezeway Airlines is the same today as it was a year ago, if inflation is taken into account by calculating prices in constant dollars. However, today 90 percent of the Toronto-to-Dallas coach tickets that Breezeway sells are discount tickets and only 10 percent are full-fare tickets, whereas a year ago half were discount tickets and half were full-fare tickets. Therefore, on average, people pay less today in constant dollars for a Breezeway Toronto-to-Dallas coach ticket than they did a year ago.

Which one of the following, if assumed, would allow the conclusion above to be properly drawn?

看到on average要想到人数的

Full-fare今年和去年是相等的
        那就都用F 然后D是今年的discount价格 d是去年的discount价格 n和m分别是票的数量
            

今年的平均票价: (90%n*D+10%n*F)/n 那么去年的平均票价: (50%m*d+50%m*F)/m

从选项出发
        选能够满足的选项
        例如B如果D=d 那么就有0.9D+0.1F=0.5D+0.1F+0.4D=0.5d+(0.1F+0.4d)<0.5d+(0.1F+0.4F)   其中F>D而且F>d 因为全票价毕竟比打折票价要高啊

full fare是一样的，去年一半是打折票，今年90％是打折票，要得出人们付的平均票价钱少了，那么assumption，就是今年打折票的价钱和去年一样。

(A) A Toronto-to-Dallas full-fare coach ticket on Breezeway Airlines provides ticket-holders with a lower level of service today than such a ticket provided a year ago. 无关

(B) A Toronto-to-Dallas discount coach ticket on Breezeway Airlines costs about the same in constant dollars as they did a year ago.

(C) All full-fare coach tickets on Breezeway Airlines cost the same in constant dollars as they did a year ago. 这个选项说的似乎 10%n*F=50%mF 但是不知道D与d 还有n与m的关系
        所以无法确定两个平均值谁大谁小

(D) The average number of coach passengers per flight that Breezeway Airlines carries from Toronto to Dallas today is higher than the average number per flight a year ago. 
        这个选项只说了n>m 但是等式中还有别的变量D和d不清楚
        所以不能确定

(E) The criteria that Breezeway Airlines uses for permitting passengers to buy discount coach tickets on the Toronto-to-Dallas route are different today than they were a year ago. 无关

至此这道题才算完结

kara---

哪有那么复杂啊。。。。。。。题目只是说90%打折，50%打折，并不是说打了90%折！！所以如果现在花费要少的话那一定是折扣是一样的，不需要列那么复杂的公式