Re: [計量] 好多題計量請教

看板GRE (GRE入學考試)作者Ykei (阿KEI)時間15年前 (2011/01/18 19:34)推噓1(1推 0噓 1→)

留言2則, 2人參與討論串13/26 (看更多)

※ 引述《balance9235 (退伍變米蟲)》之銘言： : 1. Two successive discounts of 30% and 30% are equivalent to a single discount : of p percent. : Column A Column B : p 49 ANS:A 題目看無 : 連打兩次七折=49折=discounts of 51% 2. Column A Column B : The area of rhombus 70 : ABCD if 線段AB = 10 : and 角BAC = 45度 ANS:A 菱形面積=兩個邊長10夾角45度的等腰三角形 =100/根號2 比70大 : 3 Column A Column B : The slope of a line : that passes through 2/3 : the origin and makes : a 30 degree angle with : the x-axis. ANS:B 畫個圖過原點夾30度也會過(根號3,1) 用這點算斜率=0.58 : 4. Column A Column B : The area of an isosceles : right triangle whose 4 : perimeter is 10. ANS:A (2+根號2)t=10 兩邊平方 t^2=100/6+ 4*根號2 面積=t^2/2 : 5. X≠0 , √(2x)=(3x)^1/3 : Column A Column B : x 1.2 ANS:B 兩邊六次方 (2x)^3=(3x)^2 x=9/8 : 6. How many positive 3-digit integers contain the digit 9? : (A) 180 : (B) 244 : (C) 252 : (D) 280 : (E) 648 ANS:(C) 算好幾遍，湊不出答案... 100~999共有900個數-(完全沒有9的個數)=900-(9*9*8)=252 : 7. Column A Column B : The maxiumn number of 6 : non-overlapping regions : into which 3 lines can : divide the interior of : a circle. ANS:A 比6個多把三線交於一點後其中一線往下移就會產生7個區域 : 8. Circle O is inscribed in a 3-4-5 triangle. : Column A Column B : The probability of the 1/2 : point that is not inside : the circle O if a point : is chosen at random from : inside the triangle. ANS:B 算面積比圓半徑=> 3*4=(3+4+5)*x x=1 圓面積=3.14 三角形面積=> 6-3.14 < 0.5 : 9. In hoe many ways can Alice, Betty, Carol, Diana, and Emma sit at a round : table if either Betty or Carol must sit in a certain seat and neither : Diana nor Emma can sit another certain seat? : (A) 8 : (B) 12 : (C) 18 : (D) 24 : (E) 36 ANS:(D) 不會算...隨便坐的排法就等於 5!/5=24 了... : 10. A bowl contains red, green ans white balls. The probability of choosing a : red ball is 1/3. There are 5 more green ball than red ones, and there are : 12 White balls. What is the odds against chooseing a white ball? : (A) 12/39 : (B) 12/51 : (C) 13/4 : (D) 17/4 : (E) 12/22 ANS:(C) 各有幾顆球都算出來了，不過看不懂最後一句話應該是問不選到白球的機率只是我算的答案也不是c...13/17... : 摸魚了兩天，這是今天的題目，一樣要麻煩大家了！ -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 24.27.78.55