Re: [計量] pp2-ds-17

看板GMAT (GMAT入學考試)作者dxfox (╮(’ω‘)╭ 我是宅男)時間17年前 (2008/11/26 10:47)推噓1(1推 0噓 1→)

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※ 引述《popolin29 (喵咪)》之銘言： : 17. 1097-!-item-!-187;#058&000661 : Store S sold a total of 90 copies of a certain book during the seven days of : last week, and it sold different numbers of copies on any two of the days. : If for the seven days Store S sold the greatest number of copies on Saturday : and the second greatest number of copies on Friday, did Store S sell more : than 11 copies on Friday? : (1) Last week Store S sold 8 copies of the book on Thursday. : (2) Last week Store S sold 38 copies of the book on Saturday. : Ans: B : 解答是 : (2) Sat.=38 ,90-38=52(剩下星期五,四,三,二,一,日去分這52本) : 因為星期五是要第二多的數量,先用11本試試看 : 五四三二一日 : 11 10 9 8 7 6 (這樣相加只有51本,不足52本),所以只有星期五要大於11本的時候, : 才有機會總合52,充分 : ============================================================================== : 但是我不懂為什麼四三二一日可以確認是10 9 8 7 6 的數字 : 難道不會是多或更少我知道不會超過禮拜五的11 其他星期的就不懂了 : 不知道是不是我有漏掉些什麼資訊沒注意到 : 再次麻煩各位了謝謝大家~* 我的想法是因為每天都不一樣先假設每天呈現差一的等差數列好了(最小差異的情況) 設最少那天為 X 最多那天 X+5 六天總和應該要小於或等於52 (等於就是實際上剛好呈現等差小於就是代表還要再補數字進去) 就會變成(X+X+5)6/2<or=52 2x+5<or=52/3 x<or=37/6 x必為整數所以x最大=6 然後再帶回去變成6 7 8 9 10 11 這樣才51 補一本一定只能捕在11+1 變12 所以充分 (抱歉很簡單題目被我搞的很複雜...) ============================================================================== : 還有另一題 : One member of a committee of 5 men and 8 women resigned and was not replaced. : What fraction of the remaining members were men? : (1) of the remaining members were women. : (2) The member who resigned was a woman. : 【答案】D : 但我算不出第二個答案 : 麻煩大家謝謝(~^O^~) 拜託了 : ※ 編輯: popolin29 來自: 122.120.160.234 (11/26 10:30) -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 218.167.163.226