Re: [計量] 好多題計量請教

看板GRE (GRE入學考試)作者jusushan (朱朱)時間15年前 (2011/01/14 19:25)推噓3(3推 0噓 1→)

留言4則, 2人參與討論串7/26 (看更多)

※ 引述《balance9235 (退伍變米蟲)》之銘言： : 標題: [計量] 好多題計量請教 : 時間: Fri Jan 14 17:52:30 2011 : : 1. What is the difference between the sum of the first 2003 positive even : integers and the sum of the first 2003 positive odd integers? : : (A) 0 : (B) 1 : (C) 2 : (D) 2003 : (E) 4006 ANS:(D) 我算1002 : 2-1=1 4-3=1 . . . 2003個加起來=2003 : : 2. Of the families in city X in 1994, 40% owned a personal computer. The : number of families in city X owning a computer in 1998 was 30% greater than : it was in 1994, and the total number of families in city X was 4% greater : in 1998 than it was in 1994. What percent of the families in city X owned : a personal computer in 1998? : T1998 = T1994 x 1.04 N1994 = T1994 x 0.4 N1998 = N1994 x 1.3 求N1998 / T1998 = 0.5 : (A) 50% : (B) 52% : (C) 55% : (D) 70% : (E) 75% ANS:(A) 我算(B) : : : 3. Column A Column B : : The number of ways : to exchange a 100USD 17 : bill for 5, 10, 50USD ANS:A : 5x+10y+50z=100的非負解數量 0 0 2 0 5 1 2 4 1 . .這邊共6種 . 10 0 1 0 10 0 . .這邊11種 . 20 0 0 共18種 : : 4. The median of 10, 15, x, and y is 18.5, and x < y : : Column A Column B : : X 22 ANS:C 很怪，中數就是15 and X < Y : 怎麼會等於22 : (15+x)/2=18.5 x=22 : : 5. The integer 33 is to be expressed as a sum of n consecutive positive : integers. : : Column A Column B : : The number of 2 ANS:C 10.11.12 then n=3 : possible values of n 16.17 then n=2 應該是D吧他是問n可能的值有幾個英文問題 : : : 6. In the xy-plane, the point (x,y) lies on the circle with equation : x^2+y^2 = 1 : : Column A Column B : : x + y 1.01 ANS: (D) : 更號1/2+更號1/2=1.4 1+0=1 : : 7. x + y = 5 : : Column A Column B : : The greatest value 6 : of xy ANS:A : sqrt(xy)>= (x+y)/2 xy <= 6.25 x=y=2.5時有max xy=6.25 : : 8. Paul wants tp put up a 120-feet hedge around three sides of his rectangular : garden and leave a side unfenced. If the garden has the greatest area, how : many square feet of garden will Paul hedge around? : : (A) 1,200 sq ft : (B) 1,800 sq ft : (C) 2,400 sq ft : (D) 3,000 sq ft : (E) 3,600 sq ft ANS:(B) 我算1600 : 2x+y=120 x+x+0.5y+0.5y = 120 sqrt(x*x*0.5*0.5*y*y)<=30 0.5xy<=900 xy<=1800 : : 9. x + y + z < 0 , z > x + y + 1 : : Column A Column B : z 1 ANS:D 找不出矛盾的答案 : x,y,z=-1,0,0.5 x,y,z=-2,0,1.5 : : 10. x and y are positive numbers. : : Column A Column B : : The ratio of x to y if 2 : x is 4 more than twice y ANS:A 這類型題目真的難理解... : x=4+2y x/y=(4+2y)/y=4/y +2 > 2 : : 11. If 5 cards, representes by A, B, C, D, and E, are placed in a row so that : C is never at either end, how many different arrangements are possible? : : (A) 120 : (B) 96 : (C) 72 : (D) 60 : (E) 24 ANS:(C) 我算5!-4!=96 我猜是題目either後面不完整 : 5!-2*4! C不可在兩端英文問題 : : 12. How many possible committees can be formed from a group of seven people : if each committee can have any number of members from 1 to 7? : : (A) 7 : (B) 49 : (C) 5040 : (D) 127 : (E) 98 ANS:(D) 題意不明，是每個人都可能拿1-7號的編號嗎？ : 不知道 : : 13. Pat has one penny, one nickel, one dime, one quarter and one half-dollar : in his pocket. : : Column A Column B : : The number of different : sums of money Pat can 32 : make up, assuming 0 cent : is not allowed. ANS:B : penny一分=0.01元 nickel=0.05 dime=0.1 quarter=0.25 half-dollar=0.5 重點是有這五種啦組合有2^5-1每個都可以選擇要不要拿出來除了全部不拿出來 : : 這是今天的問題，感謝大家！ : : -- : ※ 發信站: 批踢踢實業坊(ptt.cc) : ◆ From: 124.8.137.158 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 221.169.46.145