Re: [計量] 請教各位板友計量問題謝謝

看板GRE作者ron0908 (榮恩)時間13年前 (2010/09/02 00:03)推噓1(1推 0噓 4→)

留言5則, 3人參與討論串2/3 (看更多)

※ 引述《leobigpig (leobigpig)》之銘言： : 這邊先感謝昨天板友所講解的解題,我真的有搞懂昨天的問題 : 因為數學超爛,所以每天真算是在狂算數學 : 今天有些題目在這邊請教 : for how many different results of X1 + X2 cane be generated from set : X1:{7,8,9,10,11} and set X2: {25,26,27,28}? : Ans:8 用列舉就好了反正沒幾個數字寫一寫就有規律了 : There is a set five numbers, in which the average (arithmetic mean) : of the two greatest numbers is 20, the median is 7 and mode is 4. : What is the average (arithmetic mean) of the five numbers? : 不好意思我題目不太懂有五個數字假設是 a b c d e 小到大排列最大兩個的平均是20 所以(d+e)/2 = 20 => d+e = 40 中位數是7 所以 c=7 眾數是4 所以 a = b = 4 (因為其他三個的值都已經定下來了) 所以(a+b+c+d+e)/5 = (4+4+7+20)/5 = 55/5 = 11 : Ans:11 : If there are 8 people at the party and each of them shakes hands : exactly once with each at the party, then what is the total number : of handshakes exchanged at the party? : Ans:28 八個人隨便找兩個人出來握手 C8取2 = 28 : Half of the toys in a bag are small size, and a quarter of the toys : in the same bag are red toys. : Column A : The fraction of the toys in the bag which are both red and small : Column B : 1/8 : And:D : 這題不可以用兩個圈圈中間的交集算出來嗎? : X is a two-digit number, and the product of 3 and X has 9 in : its units place. : Column A : 3X : Column B : 69 : Ans: D : 題目也解不太出來 x是一個兩位數乘三以後個位數是9 = > x的個位數應該是3 3X是啥啊....其實我看不太懂這題想表達什麼如果是乘三倍的話那有可能是B9 B是任意數(3~9) 所以有可能比69大也有可能小 ANS(D) : Given that f(n+3)=F(n), F(1)=6,f(0)=5 and f(1)=4, : then what is the value of f(8)? : And:6 : In the xy-plane, the distance between (4,8) and a certain point : on the x-axis is 4√5 : Column A : The x-coordinate of the point on the x-axis : Column B : 8 假設該點為(a, 0) 則距離為 √((a-4)^2 + (8-0)^2) = 4√5 = √80 ∴(a-4)^2 + 64 = 80 (a-4)^2 = 16 a-4 = ±4 => a = 8 or 0 Ans: D : A certain set contains five integers, of which the median and : the mode are 32 and 35, respectively. If the average (arithmetic mean) : of the set is 30, then what is the lest possible value of the set? : Ans: 17 有五個數字 a b c d e 中位數是32 =>c=32 眾數是35 所以我們假設d和e都是35 平均是30 ∴(a+b+c+d+e)/5=30 => a+b+c+d+e = 150 => a+b+32+35+35 = 150 => a+b = 48 但a和b都要小於中位數32 要不然中位數會變所以a如果是最小值那b的值就要取範圍內最大我們取b = 31 ∴a = 17 : If a square with side S is inscribed in a circle, then what is the area : of the circle, in term of S? : Ans: 1/2*S^2*π 圓形裡面有一個內接正方形所以你畫圖(呃我BBS畫不出來) 應該可以得到一個算式 (S/2)^2 + (S/2)^2 = r^2 => r = S/√2 圓面積πr^2 = 1/2* π*S^2 : A group of people what to rent a loge at a ski resort for $360. : If 2 more people join the group, each person·s share for the rent : will be reduced by $9. How many people were in the original group? : Ans:8 有一群人去滑雪場租了個包廂，租金$360 如果今天再多兩個人進來的話每個人攤的錢就可以再少九塊，請問原本有多少人? 設原本有X人 360/X -9 = 360/(X+2) 整理整理通分通分 -9x^2+720-18x = 0 x^2+2x-80 = 0 (X-8)(X+10) = 0 ∴X = 8 : If for 3 consecutive years a commodity·s value increase by 20 percent : of its value the previous year, then it value after the third increase : is approximately what percent greater than its value : before the first increase? : Ans:73% : 這題目我不清楚某日用品的價格每年會上漲前一年的20% 請問漲三年後跟第一年未漲前比多了幾%? 1.2*1.2*1.2 = 1.728 ≒73% : How many square tiles, each with side 3/4 foot, are needed : to tile a square floor of side 3 feet? : Ans:16 磁磚每片3/4英呎長，總共要幾片才可以拼成一塊邊長3英呎的正方形? 3 / (3/4) = 4 每邊需要四塊 4*4 = 16 : At company X, the average (arithmetic mean) salary of the female employees : is 70 percent of the average salary of the male employees, : but the total pay roll for the female employees is 120 percent : of the total payroll for the male employees. What is the ratio : of the number of male employees to number of female employees? : Ans:7/12 有間公司，薪水的幾何平均女生是男生的70% 但總共的給付額女生是男的120% 請問公司的男女比是多少? 假設總共有男M人女F人男總共薪水為X元 X 1.2X 0.7*---- = ---- M F 整理整理通分通分 M/F = 0.7/1.2 = 7/12 : At a certain school, the school day begins at 8:15 a.m. and end at 3:15 p.m. : the day consists of a 10 minute homeroom period, a 45 minute lunch period, : and 8 class period. If the students are allowed 5 minutes to pass : from one room to the next after each period except the last, : how many minutes long is each class period? : Ans:40 有間學校他從早上8:15開始上課到下午3:15(共七小時) 有十分鐘班會、四十五分鐘午餐、八堂課，如果學生移動的時間是5分鐘，那課堂的時間應該要多長? : 文字題就是讓我大傷元氣的數學,可以請教題目意思嗎? : 謝謝好累先打到這Orz 我也大傷元氣了.... 我覺得這些題目應該不是真正作不出來的那種題目呀... 你應該沒有仔細地去讀題目吧? 而且這些題目很多都是平鋪直敘的文字而已呀... 跟閱測比起來，這個應該親切很多了吧?? 我覺得你應該可以上來寫說 "這一題我覺得是xxx或是ooo 請問是不是我誤解了它的意思" "奇怪我卡在.....請板友解答" 而不是把題目全部貼上來 "請版友幫我解答" 因為數量實在是多到一種很誇張的境界你這樣很危險唷... -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 180.177.10.201

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cassine

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ron0908

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