Re: [計量] 請教幾題數學

看板GRE (GRE入學考試)作者Ykei (阿KEI)時間15年前 (2010/11/23 17:40)推噓1(1推 0噓 1→)

留言2則, 2人參與討論串6/6 (看更多)

※ 引述《sonatach (sonata)》之銘言： 1. Par drove to work from his home, averaging 40 miles per hour, and was 12 minutes late. The next day he left home for work at the same time, took the same route, averaging 48 miles per hour, and was 7 minutes late. How far in miles is it from Pat's home to his work? Ans: 20.0 第一天距離=D 時間=T 速率 40=D/T 第二天距離不變時間=T-1/12 速率 48=D/(T-1/12) 1/12是因為第二天快了5分鐘也就是1/12小時 2. If an employee deposited $2000 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 a total of $ 10,000 in the credit union account? Ans: 41 1+[(10000-2000)/200] =41 如果要列式的話應該是這樣吧 3. If the smaller of 2 consecutive odd integers is a multiple of 5, which of the following could NOT be the sum of these 2 integers? (A) -8 (B)12 (C)22 (D)52 (E) 252 Ans: (c) 其實不要設比較好因為設方程式之後要一個一個答案帶進去算這樣要花很久不過如果要用你的方法設的話第二個奇數要設5(2x+1)+2 4. If rt > st and r > s, then which of the following must be true? (A) t > 0 (B) s > 0 (C) r > 0 (D) t < 0 (E) rs > 0 Ans: (A) 滿直觀的 5. If x < x的3次方 < x的平方, then which of the following could be the possible value of x? (A) -3/2 (B) -1/2 (C) 0 (D) 1/2 (E) 1/3 Ans: (B) 只要是負的小數都可以 6. A candidate for public office allocated 1/3 of her campaign funds for television appearances, 2/3 of the remainder for personal appearances, and the balance for newspaper advertisements. If the amount allocated for newspaper advertisements was equally divided among 4 newspapers, what fraction of her original campaign funds was allocated for each newspaper? Ans: (A) 1/18 推文有人解釋了 7. 0.0625y = x(2.5/4) Col A: x Col B: y Ans: D 移項一下 0 < 0.0625 * (2.5/4) =x/y x,y皆為正跟皆為負大小相反所以無法比較 8. If d>0 and 0 < 1- (c/d) < 1, which of the following must be true? I. c > 0 II. c/d < 1 III. c^2 + d^2 >1 Ans: I. and II. 題幹可以知道 0 < c/d < 1 只知道比值無法知道真正的值舉個例 c/d = 0.5 c=1 d=2 c^2+d^2 >1 但 c=0.1 d=0.2 c^2+d^2 <1 所以 III 不成立 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 218.166.9.74 ※ 編輯: sonatach 來自: 218.166.9.74 (11/23 12:33)