[問題]GWD 24-12

由 **evelyn_yeh** » 2006-09-05 17:14

12
During a 10-week summer vacation, was the average (arithmetic mean) number of books that Carolyn read per week greater than the average number of books that Jacob read per week?
(1) Twice the average number of books that Carolyn read per week was greater than 5 less than twice the average number of books that Jacob read per week.
(2) During the last 5 weeks of the vacation, Carolyn read a total of 3 books more than Jacob.

ans(A)
我怎麼算都是 E 呀

由 **evelyn_yeh** » 2006-09-06 16:45

請各路高手幫忙,我月底就要考了 orz

由 **simonyu** » 2006-09-06 22:33

假設二人平均每週唸的書分別為C及J
A)由題目可得2C>2J-5,化簡後為C-J>-2.5, not sufficient
B)僅有最後幾週，無法推知全月平均每週閱讀數，not sufficient

我也是答案E

由 **evelyn_yeh** » 2006-09-07 10:13

2C>2J-5 是如何導出 C-J>2.5 的??
2C>2J-5 => C>J-2.5 => C-J> -2.5 => C>J, or C<J,不充分呀
B也不充分呀

我是不是忽略了什麼??

由 **simonyu** » 2006-09-07 11:21

對不起，移項的時候沒注意，已經修改了，結果答案跟你一樣。
好像沒幫上忙～

由 **evelyn_yeh** » 2006-09-07 11:26

這題我有搜尋過 ,好像沒人討論....還是有討論,我沒搜到??

由 **Penny Lee** » 2006-10-16 01:01

換個方式說2C>2J-5, 為2C+5>2J =>C+2.5>J

可以得出J>C

由 **navywhite0425** » 2006-11-03 16:36

關於這題
我選A

不知道是我閱讀有問題才對還是怎樣
反正大家參考一下

選項1)說
2C read per week was greater than 5 less than 2J

so 我覺得是 2J > 2C > 5
所以
J > C 充分

選項2) 只用後面幾個月無法得知全部不充分

所以我選A

參考參考

由 **kaijen** » 2007-07-31 10:26

請問這是什麼意思呀??
Twice the average number of books that Carolyn read per week was greater than 5 less than twice the average number of books that Jacob read per week

1. 2C>2J-5 答案選E
2. 2J>2C>5 答案選A

有人可以解答嗎?
thx

[問題]GWD 24-12

[問題]GWD 24-12

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