Re: [問題] PP 數學請教
※ 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
假設參加早場的人為A 午場的人為B
則128人指的是 A+B (AＵB)
1. 為 AｎB (交集) 只能推得參加的總人數 A+B-(AｎB)=參加總人數
2. 7/8參加午場 所以1/8參加早場 128* (1/8) = 16
答案為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
題目指出 沒有任合一個地區會超出另一個地區 10%人口
假設一地區最少人口為a 別的地區那最多人口就是 a* 110% = 1.1a
a有最小值的情況---> 其他所有10個地區都是剛好超出a有10%的人口數
所以 (1.1a+1.1a+.....1.1a)+a = (1.1a)*10 + a = 132000
解得a為11000人
恩~ 我是這樣想的 囧>
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※ 編輯: jjhgfr 來自: 61.216.196.118 (09/27 11:16)
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09/27 21:42, , 1F
09/27 21:42, 1F
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