[問題]GWD6-Q22,Q28

[myron]

Q22:
A certain company assigns employees to offices in such a way that some of the offices can be empty and more than one employee can be assigned to an office. In how many ways can the company assign 3 employees to 2 different offices?
A.5 B.6 C.7 D.8 E.9
答案: D

Q28:
Last Sunday a certain store sold copies of Newspaper A for $1.00 each and copies of Newspaper B for $1.25 each, and the store sold no other newspapers that day. If r percent of the store’s revenues from newspaper sales was from Newspaper A and if p percent of the newspapers that the store sold were copies of newspaper A, which of the following expresses r in terms of p?
A.100p / (125 – p)
B.150p / (250 – p)
C.300p / (375 – p)
D.400p / (500 – p)
E.500p / (625 – p)
答案: D

有那位高手可以幫我解答嗎?感謝啦. :'(

[魚]

Q22:
A certain company assigns employees to offices in such a way that some of the offices can be empty and more than one employee can be assigned to an office. In how many ways can the company assign 3 employees to 2 different offices?
A.5 B.6 C.7 D.8 E.9
答案: D

Q28:
Last Sunday a certain store sold copies of Newspaper A for $1.00 each and copies of Newspaper B for $1.25 each, and the store sold no other newspapers that day. If r percent of the store’s revenues from newspaper sales was from Newspaper A and if p percent of the newspapers that the store sold were copies of newspaper A, which of the following expresses r in terms of p?
A.100p / (125 – p)
B.150p / (250 – p)
C.300p / (375 – p)
D.400p / (500 – p)
E.500p / (625 – p)
答案: D

有那位高手可以幫我解答嗎?感謝啦. :'(

hello , for Q22 , 答案應該是 8 . 抓3個人分到兩個辦公室裡.每個人都有兩個選擇
2X2X2=8

forQ28 , 這道題我到現在還是被困著. 我卡住的地方是 :

1. 我不確定copies of Newspaper A 是不是 報紙A的複本 ?
若不是的話 ,r percent of the store’s revenues from newspaper sales was from Newspaper A and if p percent of the newspapers that the store sold were copies of newspaper A 為何有new A 跟 copies of newspaper A 的不同

2.題目談的是 copy of A /B 的售價 . 那news A 的售價是多少 ?


3.一度懷疑沒有copy 及 new A 跟 copies of newspaper A 的不同
考慮是後面的copies of newspaper A 為誤植 ,但改為B後 還是算不出答案 :'(

頂一下 ,請高人來相助嚕 ;)

[Behemoth]

28.
設a賣了x份,b賣了y份
則根據原題,
可列為 p/[p+(1-p)1.25]=r

化簡一下就是答案d囉

如果說不這樣列式的話
用設a賣x份,b賣y份
然後列兩個式子
(1*x+1.25*y)*r%=1*x
(x+y)*p%=x

這樣我覺得很難化簡,我化了半天還是那個樣....所以用上面第一種好了

[魚]

28.
設a賣了x份,b賣了y份
則根據原題,
可列為 p/[p+(1-p)1.25]=r

化簡一下就是答案d囉

如果說不這樣列式的話
用設a賣x份,b賣y份
然後列兩個式子
(1*x+1.25*y)*r%=1*x
(x+y)*p%=x

這樣我覺得很難化簡,我化了半天還是那個樣....所以用上面第一種好了

B爺 , 我發現我現在完全退化成豆腐腦(H)......... :-S

所以 ,尼 不覺得題目的敘述有我上面遇到的問題 ?

請問 :'( p 是啥的比例 ?

[吳志道]

ㄎㄎㄎ 我也看好九 我的英文要加強>"<~

p percnt 是份數喔 所以 total=x+y 份 x/ x+y= p%

了ㄇ ^^~

幫B熊 補充

所以囉 total 賺的 比例 1*p% +1.25(1-p%)

A賺的% 1*p% / [1*p% +1.25(1-p%)] =r%

^^

[Behemoth]

28.
設a賣了x份,b賣了y份
則根據原題,
可列為 p/[p+(1-p)1.25]=r

化簡一下就是答案d囉

如果說不這樣列式的話
用設a賣x份,b賣y份
然後列兩個式子
(1*x+1.25*y)*r%=1*x
(x+y)*p%=x

這樣我覺得很難化簡,我化了半天還是那個樣....所以用上面第一種好了

B爺 , 我發現我現在完全退化成豆腐腦(H)......... :-S

所以 ,尼 不覺得題目的敘述有我上面遇到的問題 ?

請問 :'( p 是啥的比例 ?

p就是賣的全部裡面有p%是a啊

啊copies....報紙不都是影印一份一份的嗎...
所以就用copies啊...

[吳志道]

Q22 也提供一下比較呆的思路
三個人都在同一間 [0][3] [3][0] ===>2
分成2個人1個人 [2][1]===>C(3,2)C(1,1)乘2 (因為會[1][2])=6

2+6=8

[myron]

Q22
還是不太懂......
難道題目中some of the offices can be empty and more than one employee can be assigned to an office不須要考慮嗎???

[吳志道]

房間是可以空的 and 一間也可以超過一個以上的人
(題目不用說at least 是因為 數字設計已經限死情形)
了ㄇ ^^

[魚]

房間是可以空的 and 一間也可以超過一個以上的人
(題目不用說at least 是因為 數字設計已經限死情形)
了ㄇ ^^

是啊 :D

[myron]

了解啦,是我誤會題意了~~

[bestjavabean]

28.
設a賣了x份,b賣了y份
則根據原題,
可列為 p/[p+(1-p)1.25]=r
請問 我怎麼因式分解 都算不出來答案ㄟ
怎麼算的阿D
謝謝

[bestjavabean]

如果同成400 應該是400P/(1.25*400+0.25P*400)=r 阿
答案不就是 400P/500+100P

[JS]

如果同成400 應該是400P/(1.25*400+0.25P*400)=r 阿
答案不就是 400P/500+100P

I think you should put % in the equation.
So that
r%=p%/p%+1.25 - 1.25p%
r%=p%/p%(1-1.25)+1.25
r%=p%/1.25-0.25p%
r=100p%/1.25-0.25p%
r=p/1.25-0.0025p

times 400 on both numerator and denominator and you get the answer
400p/500-p

cant believe I actually solve this problem.... first I have to thank my parents...second, all the crews who work with me.......
sorry get too carry away..