Re: [計量] PP2-PS107、108、110問題請教

看板GMAT (GMAT入學考試)作者Merica (美加文教)時間15年前 (2011/03/16 17:51)推噓0(0推 0噓 0→)

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※ 引述《Q7 (T^T)》之銘言： : PS2 107 : Table: Ann $450,000 : Bob $360,000 : Cal $190,000 : Dot $210,000 : Ed $680,000 : The table above shows the total sales recorded in July for the 5 salespeople : at Acme Truck Sales. It was discovered that one of Cal's sales was : incorrectly recorded as one of Ann's sales. After this error was corrected, : Ann's total sales were still higher than Cal's total sales, and the median of : the 5 sales totals was $330,000. What was the value of the incorrectly : recorded sale? : (A) $30,000 : (B) $48,000 : (C) $90,000 : (D) $120,000 : (E) $140,000 : 一直想不透答案為什麼是D..... : 想看看強者的見解，我算出的答案是A : 我在想是不是我沒搞懂題目? : It was discovered that one of Cal's sales was incorrectly recorded : as one of Ann's sales. 這句話我真的不是很懂... ◎回答問題PS2 107： Median意指這5 sales金額，依序由小排到大，排正中央之值所以(1)median=330000=450000-X, X=120000, Ann=330000 或(2)median=330000=190000+X, X=140000, Ann=310000, Cal=330000 因題意說Ann>Cal 所以(2)不成立, (1)成立Ｘ=120000, 答案(D) : PS2 108 : 畫出來是這樣...應該是對的。 : 1 0 : ├──┴┼─┴─┼┴──┴┼─┴┼┴─┤ : On the number line above, the segment from 0 to 1 has been divided into : fifths, as indicated by the large tick marks, and also into sevenths, as : indicated by the small tick marks. What is the least possible distance : between any two of the tick marks? : (A) 1/70 : (B) 1/35 : (C) 2/35 : (D) 1/12 : (E) 1/7 : 這題完全陣亡.... 答案是B ◎回答問題PS2 108 3/5 - 4/4 = 1/35 所以答案是B : PS110 : During a trip on an expressway, Don drove a total of x miles. His average : speed on a certain 5-mile section of the expressway was 30 miles per hour, : and his average speed for the remainder of the trip was 60 miles per hour. : His travel time for the x-mile trip was what percent greater than it would : have been if he had traveled at a constant rate of 60 miles per hour for the : entire trip? : (A) 8.5% : (B) 50% : (C) x/12% : (D) 60/x% : (E) 500/x% : 我是算出C，但是答案卻是E...想好久真的想不透囧 : 請高手指點了非常感謝 ◎回答問題PS110 5-mile section費時 = 5/30 = 1/6 hr 其餘費時 = (X-5)/60 全程定速60 miles/hr 費時= X/60 題目所問之% = [ (X-5)/60 + 1/6 ] / (X/60) * 100% = [ (X-5+10-X)/60 ] / (X/60) * 100% = 5/X * 100% = 500/X % 所以答案E （以上內容由美加黃冠文教授提供） -- ▅▅▅▅ ▅▅ ▅▅▅ ▅ ▅▅ ▅▅▅ █ █ █ █▅ █▄█ ▄ █ █▄█ █ █ █ █▄ █◥▅ █ █▅ █ █ -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 114.36.60.200