Re: [計量] 幾題數學請教
※ 引述《sead11 (Xavi)》之銘言：
: 1.if x and y are integers and xy+1 is even,
: which of the following must be odd?
: (A)(x^2)(y^2)
: (b)y(x+1)
: (c)x(x+y)
: (d)(x+y)^2
: (e)(x+1)(y+1)
: 答案給的是A
: 但我覺得是D
: 想確定一下答案有沒有問題
: 2. when n articles are sold for p dollars each,
: the revenue obtained from the sales is $1 more
: than it would be if the price per article were
: $1 higher and one less article were sold.
: which of the following gives n in terms of p?
: (a)n=(p-1)/(p+1)
: (b)n=p+2
: (c)n=p+1
: (d)n=p
: (e)n=p-1
n個東西，一個賣p元 (收入等於np)
當把售價提高1元(同時會少賣出去一個)的情況下，多賺了1元 A_A
(n-1)(p+1) = np + 1
==> n= p+2
ans: b ?
: 這題是我看不懂題目在問什麼
: 想請教一下板上的大家
: 謝謝
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 218.167.73.131
→
10/20 01:13, , 1F
10/20 01:13, 1F
→
10/20 01:21, , 2F
10/20 01:21, 2F
討論串 (同標題文章)