GWD27-33

[CherrieLi]

33. The table above shows the results of a survey of 100 voters each responded "favorable" or "unfavorable" or "not sure" when asked about their impressions of candidate M and of candidate N. What was the number of voters who responded "favorable" for both candidates?

(1)The number of voters who did not respond "favorable" for either candidate was 40.
(2)The number of voters who responded "unfavorable" for both candidates was 10.

答案是A.... 請問是怎麼來的呢?

表格簡略如下

---------------------Favorable Unfavorable Not Sure
Candidate M------------- 40------- 20------- 40
Candidate N------------- 30------- 35------- 35

[YH32480]

我個人覺得...這題不要想得太複雜 ...

我的rationale如下：
(F = Favorabel, U=unfavorable, N=Not sure)
所有排列組合的可能性 for candidate (M, N) 是 --
a. (F, F)
b. (F, U)
c. (F, N)
d. (U, F)
e. (U, U)
f. (U, N)
g. (N, F)
h. (N, U)
i. (N, N)
總人數=(a+b+c+....i) = 100, 問 a = ?
條件
(1) a 以外的總和 =40, 即 (b+c+d....i)=40, 所以可得出 a = 100-40 = 60【sufficient】
(2) e = 10 【not sufficient】
為了解釋方便才拉里拉雜寫了一堆算式, 但真正做題時, 應該不需花太多時間...

不知我的淺見各位大大是否同意

[CherrieLi]

嗯, 這個方法很棒耶, 一目瞭然
謝謝你呀 ^^

[jinoliway]

(好久沒來了）
最近因為要考HSBC所以拿GMAT複習一下，發現以前不會的現在還是不會，但是思路卻比較清楚一點點。
這裡看到yh32480的說法，豁然開朗，但是覺得怪怪的

應該e+f+g+h+i=40，所以a+b+c+d=60
又因b+c+d=70，所以a=10

報告完畢！