Re: [計量] 數學問題
※ 引述《hsingchih (請賜我GRE高分吧!!)》之銘言：
: A rectangular rug covers half of a rectangular floor that is 9 feet wide
: and 12 feet long. If the dimensions of the rug are in the same ration as
: those of the floor, how many feet long is the rug?
: (A) 6
: (B) 21/2
: (C) 2*更號7 (不知道怎麼打更號)
: (D) 6*更號2
: (E) 4*更號6
: Ans: D
面積要地板的一半所以=>長*寬＝1/2*(12*9)
又長寬比要跟地板的長寬比相同=>(12*t)*(9*t)=1/2*(12*9)
^^^^ ^^^
地毯 (長) (寬)
=>t^2=1/2 =>t=1/√2 故 地毯的長=12*(1/√2)=6√2
: If x and y are integers and x＞y＞0, how many integers are there between,
: but not including x and y?
: (A) x-y
: (B) x+y
: (C) x-y-1
: (D) x+y-1
: (E) x-y+1
: Ans: C
舉例：10>5>0 => 9 8 7 6 共四個 10-5-1=4
=> x-y-1
: X,Y, and Z are positive integers, and Z＞X＞Y.
: Column A The remainder when Z is divided by X
: Column B The remainder when Z is divided by Y
: Ans: D
Column A => X>remainder>=0
Column B => Y>remainder>=0
結論=> Column A的餘數範圍比Column B大
舉例：X=5 Y=3 Z=18 時 Column A =3
Column B =0
Z=20 時 Column A =0
Column B =2
故答案是D
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 61.231.198.25
討論串 (同標題文章)