Re: [計量] Two tanks, X and Y, are filled ...

看板GRE (GRE入學考試)作者Whirligig (New Revolution)時間17年前 (2008/11/10 01:01)推噓1(1推 0噓 0→)

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※ 引述《tkmax (事事如意)》之銘言： : 做練習遇到的幾題想不出來的問題... : 拜託各位大大幫解~~ 謝謝 <(_ _)> : 1. Two tanks, X and Y, are filled to capacity with jet fuel. : Tank X holds 600 gallons more than tank Y. : If 100 gallons of fuel were to be pumped from each tank, : tank X would then contain 3 times as much fuel as tank Y. : What is the total number of gallons of fuel in the two full tanks? : Ans: 1400 這題我想可能是題目看不懂（因為我當時做BB也是題目都搞不太懂） more than, as much as....這種敘述剛開始真的讓我很頭痛，很常弄相反XD 或是沒注意到題目最後是問"X+Y＝？" X=y+600.....................(1) (x-100)=3(y+500)............(2) 用兩個個式子來解，將（1）代入2 可以算出Y＝500，X＝1100 X+Y＝1600 : 2. If the value if the expression above is to be halved by : doubling exactly one of the five numbers a,b,c,d, or e, : which should be double? : Ans: d 這題你題目沒打完，如果我沒記錯，應該也是BB的題目？應該是一個分數/一個分數（我不會用BBS打底線= =）我猜題目是是例如（A-B）/(C+D) / D/E 所以上面分數的分母＊下面分數的分子會成會最後數的分母，分母減少1/2，總數就會變成2倍，所以答案是D （不過這題因為沒有題目，所以只能猜測....） : 3. A part-time employee whose hourly wage was increased by : 25 prescent decided to reduce the number of hours worked : per weeks so that the employee’s total weekly income would : remain unchanged. By what percent should the number of hours : worked be reduced? : Ans: 20% 這種題目，我通常用數字來算（因為用％我常越算越混亂XDD）首先，成長25% ==> 100-->125 就是成長25% ：（125-100）/100=25% 接著，題目問說從125變回100的話，是減少多少，所以變成（125-100）/125=20% : 4. For telephone calls between two particular cities, a telephone : company charges $0.40 per minute if the calls are placed : between 5:00 a.m. and 9:00 p.m. and $0.25 per minute if the c : alls are placed between the two cities placed at 1:00 p.m. : was $10.00, how much would a call of the same duration have cost : if it had been placed at 11:00 p.m.? : Ans: $6.25 這題我看不太懂（抱歉^^"） : 5. If X and Y are sets of integers, X#Y denotes the set of integers : that belong to set X or set Y , but not both. : If X consists of 10 integers, Y consists of 18 integers, : and 6 of the integers are in both X and Y, then X#Y consists : if how many integers? : Ans: 16 簡單來說就是：10 + 18 - (2*6)＝16 畫兩個圈圈X跟Y，中間兩圓要有交集.... 其實就會發現X＝x+交集＝10...........（1） Y＝y+交集＝18...........（2）（1）+（2）==>X+Y=10+18-2個交集（交集等於6）所以就是10+18-12＝16 小小的建議：如果是BB的題目，可以稍微註明一下，這樣萬一題目打字錯誤或是題目太麻煩...有BB的板友就可以翻書看看囉^^ -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 218.171.181.176