Re: [計量] 有些文字繁瑣的計量請教課為板友

看板GRE (GRE入學考試)作者snake741018 (snake)時間15年前 (2010/08/31 21:31)推噓0(0推 0噓 0→)

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※ 引述《leobigpig (leobigpig)》之銘言： : 這邊有些文字繁瑣的計量數學,我時在不懂 : 這邊請教位味版友,題目有點多真的有點不好意思 : 題目如下: : In the rectangular coordinate system, if points (5,9), (X,1), and (4,5) : lie on the same line, what is the value of X? : Ans: x=3 這題看是用向量算或是用直線來算都ok 個人偏好直線==> 用(5,9)(4,5)兩點得出來 4x-y=11 再代入(X,1)得到 X=1 : S=7^0+7^1+7^2+…+7^20 : Column A: The remainder when S id divided by 14 : Column B: 1 : Ans: C 他要求S除14之後的餘數(14倍數必需同時滿足被7和2除盡) 把S拆開來看吧 S= 7^0+(7^1+7^2+.....+7^20) = 1+7(1+7^1+7^2+....+7^19) -->提出7 ~~~~~~~~~~~~~~~~~~~ 每一項均為奇數(共20項) 故20項奇數相加後為偶數==>偶數為2的倍數所以括號內可以被14整除故 S mod 14 =1 答案C : A commuter drive to work 5 days a week. On the average, : the trip to work takes 1 hour and 10 minutes : and the trip home take 1 hour and 5 minutes. : If the commuter works 40 weeks a year, : the total commuting time for one year is equivalent to approximately : how many 8-hour working days? : Ans: 56 這題~就純粹的運算式每周上班五天(每天上班花1hr10min/回家花1hr5min) 如果一年總共上班40週~總共的通勤時數約是每天上班8小時的幾倍(記得單位是天數) 1hr 10min + 1hr 5min =2hr 15min = 2.25hr 2.25 * 5 * 40 / 8 = 56.25 約56天! (一年總時數) : 這邊我if 後就有點混亂了 : Carpeting costs $9 per square meter. : If there is an installation charge of $5 per room, : what is the total cost, including the installation charge, : of carpeting installed in 3 rectangular rooms, each 3 meters by 6 meters? : Ans: 501 每平方公尺需要9元...每間房間多收5元現在有三間3*6平方公尺的房間需要多少錢! 3 * 6 * 9 * 3 + 3 * 5 = 501 : A worker stated to work on the 1st day of a certain month : and worked for 8 consecutive days. If the worker earned $20 per day : on each odd-numbered day and $30 per on each even-numbered day, : what percent of the total amount earned on the 8 days was earned : on the odd-numbered days? : 我算 60% : Ans: 40% 這題我也算60% : If X is the greatest four-digit number such that the sum of the digits : is 23 and no two digits are the same, which of the following is NOT a digit : of x? : Ans: 7 X是最大的四位數(且四位數字加起來的和為23) 任兩位數皆不同!問下列何者不可能為X內的數字 9860 這應該是最大且符合題目條件的數字了! (解法就數值大的數字從最前面的位數先排就好，排完9和8之後再來考慮和為23的問題) : Two people invested equal amounts of money for one year, : one at 8 percent simple annual interest and the other at 12 percent simple : annual interest. If after the one year the amounts of money invested : plus interest differed by $50, what was the original amount invested : by each person? : 不好意思這題我想了很久還是看不懂 : Ans: $1250 他是指..有兩位投資者擁有相同資本...一位投資者的利息是以年利率8%單利計算另一位投資者的利息是以年利率12%單利計算...在投資一年後..兩位的本利和相差50 問當初的資本為多少? 設當初資本為x x * (1.12 - 1.08) = 50 x= 1250 : If an employee deposited $2,000 in a new credit union account : and made a single $200 deposit during each month thereafter, : after how many deposits will the employee have deposited total of $10,000 : in the credit union account? : 我算40 因為第一次不能存錢要從第二次開始算嗎? : Ans: 41 這題我的感覺也會想寫40...問問其他強大的版友! : A tank in the shape of a rectangular solid is being fill with water : at a constant rate so that the top surface of the water rises 7 meters : every 7 hours. If the area of this rising surface is 12 square meters, : what is the rate, in cubic meters per minute, at which the water : is entering the tank? : 我總是被文字題而煩惱 : Ans: 0.2 : Two strings with equal length are to be shaped, without overlap, : into a circle and a square, respectively. : Column A: The area of the circle. : Column B: The area of the square. : Ans: A : 請教各位板友謝謝 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 61.20.186.198 ※ 編輯: snake741018 來自: 61.20.186.198 (08/31 21:33)