Re: [問題] 請問幾題數學

看板GRE (GRE入學考試)作者Merica (美加文教)時間14年前 (2011/06/15 10:40)推噓0(0推 0噓 0→)

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※ 引述《DREAM11 (夢魂新苑)》之銘言： : 請問幾題GRE的數學...謝謝<(_ _)> : For certain farm, soybean production increased by 25 percent from year X to : year Y, and the selling price of soybeans decreased by 25 percent from year X : to year Y. If the entire soybean production was sold each year, approximately : what was the percent change in the revenues from the sale of the soybeans : from year X ti year Y? : (A) 56% decrease (B) 6% decrease (C) No change (D) 6% increase (E) 56% : increase : Answer: B 設原產量P，原售價S，後來產量變成1.25P，售價變成0.75S， 1.25P x 0.75S - PS／PS x 100% = -6.25% : ---------------------------------------------- : p.223 : Which of the following sets of numbers has the greastest standard deviation? : (A) 2,3,4 (B) 2.5, 3 , 3.5 (C) 1, 1.25, 1.5 (D) -2 , 0 , 2 (E) -20 , 21 , 21.5 : Answer: D (為什麼不是E呢 @@) (E) -20, 21, 21.5之average = 7.5 Sd = √(-20-7.5)^2 + (21-7.5)^2 + (21.5-7.5)^2／3 = 19.4 : --------------------------------------------- : p.224 : Workers at Companies X and Y are paid the same base hourly rate. Workers at : Company X are paid 1.5 times teh base hourly rate for each hour worked per : week in excess of the first 37, while workers at Company Y are paid 1.5 times : the base hourly rate for each hour worked per week in excess of the first 40. : In a given week, how many hours must a Company X worker work in order to : receive the same pay as a Company Y worker who works 46 hours? : (A) 46 (B) 45 (C) 44 (D) 43 (E) 42 : Answer: B 設base hourly rate = B, X為Company x工人應工作時數 37B + (X-37) x 1.5B = 40B + (46-40) x 1.5B X = 45 : --------------------------------------------- : p.226 : The numbers in the list above are ordered from least to greastest. If the : average (arithmetic mean) is 2 grater than the median, what is the value of x : ? : (A) 22 (B) 20 (C) 17 (D) 16 (E) 15 : Answer : A (請問...它的題目是不是沒有給完整呢) 題確實不完整 : ------------------------------------------------ : p.227 : a : _______________________ : b : _____________________________ : ab : ___________________________________ : The length of the line segments are a, b , and ab, respectively. The line : segments are drawn to scale. : 問: a 和 1 誰比較大? : Answer: A : (是不是題目不完整@@) 題確實不完整 : ------------------------------------------------- : 以上...麻煩了!! 謝謝<(_ _)> (以上內容由美加黃冠文老師提供) -- ▅▅▅▅ ▅▅ ▅▅▅ ▅ ▅▅ ▅▅▅ █ █ █ █▅ █▄█ ▄ █ █▄█ █ █ █ █▄ █◥▅ █ █▅ █ █ 7/2(六)下午2：00美加文教新制GRE&字彙三合一免費講座莫清崴博士/江璞教授主講歡迎蒞臨 http://www.merica.com.tw/event/20110702/ -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 114.36.53.186