※ 引述《KMI (無奈)》之銘言： : DS: 剛剛模考做到 : A certain one-day seminar consisted of a morning session and an afternoon : session. If each of the 128 people attending the seminar attended at least : one of the two sessions, : how many of the people attended the morning session only? : 1) 3/4 of the people attended both sessions. : 2) 7/8 of the people attended the afternoon session. : 答案: B 畫圈圈圖會比較好理解 學生有三種(M: morning session; A:Afternoon session) I. M but not A II. both M & A III. A but not M 1)只知道M & A交集的人數 --> not sufficient 2)知道I+II=7/8*128=112,又題目給說所有的學生=I+II+III 所以可以得知attend the M only的人數有128-112=7人 ---> sufficient! Therefore, choose the answer B : A certain city with a population of 132,000 is to be divided into 11 voting : district, and no district is to have a population that is more than 10% : greater than the population of any other district. What is the minimum : possible population that the least populated district could have? : 1. 10700 : 2. 10800 : 3. 10900 : 4. 11000 : 5. 11100 : 答案: D 題目重點"任何一個district的人均不大於另一個district人數的10%" --->即最多和最少人數的district差10% 設這11個district中人數最小者有x人 最極端的情形...就是另外10個district人數均是1.1x 則1.1x*10+x = 132000 求解得出x=11000 Choose answer D --

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