Re: [計量] 求解幾題數學

看板GRE (GRE入學考試)作者Merica (美加文教)時間15年前 (2011/05/27 12:03)推噓0(0推 0噓 0→)

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※ 引述《bonitala (Bonita)》之銘言： : 今天開始算計量 : 發現太久沒碰數學，看題目實在很花時間 : 以下題目解不出答案 : 麻煩大家幫幫忙嚕!! : i 12345678 : n 12232424 : 1.in the table above, the number in the row labeled i form the sequence : of positive integers and each number in the row labeled n is the number of : different positive divisors of the corresponding integer i. what is the value : of n that corresponds to the integer 36? 這題實在找不出規律>< : A)4 B)6 C)7 D)8 E)9 n欄的數字是對應i欄數字之因數的個數，例如1只有個因數，2有兩個，依此類推，問36有幾個因數？ Ans：1,2,3,4,6,9,12,18,36共9個 : 2.if the organization were to sell n ticket for a theater production, the : total revenue from ticket sales would be 20% greater than the total costs of : production. if the organization actually sold all but 5% of the n tickets, the : total revenue from tickets sales was what percent greater than the total costs : of the production? : A)4% B)10% C)14% D)15% E)18% 設每張票售價x元，則x．n = 1.2 (cost) 現在只賣出95%的票，則收入為0.95xn 所以0.95xn = 0.95 (1.2 cost) = 1.14 (cost) Ans：選C : 3.one-fifth of the light switches produced by a certain factory are defective. : Four-fifth of the defective switches are rejected and 1/20 of the : non-defective switches are rejected by mistakes. if all the switches not : rejected are sold, what percent of the switches sold by the factory are : defective? : A)4% B)5% C)6.25% D)11% E)16% 生產的開關1/5有瑕疪，其中4/5被退貨，無瑕疪的則有1/20被誤退，其餘全售出，問售出的裡面有瑕疪占百分之幾？設生產100組有瑕疪 = 20，其中16組被退，因此4組售出無瑕疪 = 80，其中4組被退，因此76組售出共售出80組，其中4組有瑕疪 Ans：B : 4. Which of the following CANNOT be the sum of 3 or more consective integers? : A)1 B)2 C)3 D)4 E)5 三個或是三個以上連續(consecutive)整數之和不可能為幾？ 0 + 1 + 2 = 3 -1 + 0 + 1 + 2 = 2 -3 + -2 + -1 + 0 + 1 + 2 + 3 + 4 = 4 -4 + -3 + -2 + -1 + 0 + 1 + 2 + 3 + 4 + 5 = 5 因此選(A) : 5.What is the probability of selection and odd number at random from the set : of {1,2,...n},in which n is an odd number and greater than 50? : Ans: : 1/2+1/2n 此題題意不清，無法解答（以上內容由美加江璞老師提供） : 以上，2.3.4.5基本上題目看不太懂 : 跟同學討論也無解! : 多謝大家耐心指教啦!!^^ -- ▅▅▅▅ ▅▅ ▅▅▅ ▅ ▅▅ ▅▅▅ █ █ █ █▅ █▄█ ▄ █ █▄█ █ █ █ █▄ █◥▅ █ █▅ █ █ 5/28(六)早上10：00美加文教新制GRE解題免費講座莫清崴博士主講歡迎蒞臨 http://www.merica.com.tw/event/20110528/ -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 114.36.61.218