GWD 12-4 13-7 13-23

[stan(屎蛋)]

GWD 13-7
For a certain race, 3 teams were allowed to enter 3 members each. A team earned 6 – n points whenever one of its members finished in nth place, where 1 ≤ n ≤ 5. There were no ties, disqualifications, or withdrawals. If no team earned more than 6 points, what is the least possible score a team could have earned?

A. 0
B. 1
C. 2
D. 3
E. 4
不太董題目意思......

GWD 13-23
In the decimal representation of x, where 0 < x < 1, is the tenths digit if x nonzero?
(1) 16x is an integer.
(2) 8x is an integer.

這題答案是啥阿??...我看GWD解答都不一樣...我選D

GWD 12-4
If the product of the digits of the two-digit positive integer n is 2, what is the value of n ?
(1) n is odd.
(2) n is greater than 20.
覺得這題怪怪的...我選C.......答案是D...

幫幫愚笨的屎蛋吧.....謝謝

[homaru]

GWD 13-7
For a certain race, 3 teams were allowed to enter 3 members each. A team earned 6 – n points whenever one of its members finished in nth place, where 1 ≤ n ≤ 5. There were no ties, disqualifications, or withdrawals. If no team earned more than 6 points, what is the least possible score a team could have earned?

A. 0
B. 1
C. 2
D. 3
E. 4

3個隊伍,每一隊3個人,每一名得6-n分,n是名次
第一名得6-1=5分,第二名4分,第三名3分,第四名2分,第五名1分,沒有平手棄權不合資格...
如果沒有隊伍得分超過6分
(5+1)(4+2)(3)-->每對最低得分為3
最低得分2 or 1都不可能,因為就會有隊伍得分超過6分

[homaru]

GWD 12-4
If the product of the digits of the two-digit positive integer n is 2, what is the value of n ?
(1) n is odd.
(2) n is greater than 20.

從題目就推出n=21 or 12
1)n奇數-->n=21
2)n>20-->n=21
兩個都充分 (H)

[stan(屎蛋)]

川叔......缸溫..............小弟先謝過了

[homaru]

http://www.formosamba.com/phpBB3/viewtopi ... r&start=30
第2題在這邊~

[asicschu]

GWD 13-7
For a certain race, 3 teams were allowed to enter 3 members each. A team earned 6 – n points whenever one of its members finished in nth place, where 1 ≤ n ≤ 5. There were no ties, disqualifications, or withdrawals. If no team earned more than 6 points, what is the least possible score a team could have earned?

A. 0
B. 1
C. 2
D. 3
E. 4

3個隊伍,每一隊3個人,每一名得6-n分,n是名次
第一名得6-1=5分,第二名4分,第三名3分,第四名2分,第五名1分,沒有平手棄權不合資格...
如果沒有隊伍得分超過6分
(5+1)(4+2)(3)-->每對最低得分為3
最低得分2 or 1都不可能,因為就會有隊伍得分超過6分

這題OG裡面有吧... :P

[訪客]

GWD 13-23
In the decimal representation of x, where 0 < x < 1, is the tenths digit if x nonzero?
(1) 16x is an integer.
(2) 8x is an integer.


看過H大給的連結了
還是不懂
B對的話
我嘗試的用代數的方式發現到0.125跟0.25乘上八都會得整數
答案怎摩會是B呢???

[吳志道]

題目問 ==>x的十分位小數是否為0 (B) X的十分位可以判斷一定不為0阿^^ 所以充分
A得X的十分位 就不一定囉 1/16 為0 之後1/8...1/4 都不為0 所以不充分

[kikisky]

喂~現在是怎樣??問題都擠在同一帖??(d25)
豬大你麻幫幫忙ㄋㄟ~~
(不知不覺火氣上升的叮噹∼sorryv_v)

[訪客]

A得X的十分位 就不一定囉 1/16 為0 之後1/8...1/4 都不為0 所以不充分

吳爺,請問一下這一句話你是怎麼推的,可不可以在白話一點

[homaru]

A得X的十分位 就不一定囉 1/16 為0 之後1/8...1/4 都不為0 所以不充分

吳爺,請問一下這一句話你是怎麼推的,可不可以在白話一點

1/16=0.0625-->十分位是0
1/8=0.125, 1/4=0.25-->十分位都不為0

[吳志道]

再補充一下 因為16X要為整數 當0<x<1 所以X最小為1/16...再以此類推
==>x=1/16 十分位為0
[tab]之後x=1/8...1/4 十分位都不為0 所以不充分


不知是否解決了M大的困惑 ^Q^

[訪客]

感謝兩位大大的解題...
醍湖灌頂中........

[kobeda0628]

謝謝牛人的解惑

[Flory]

報告, 12-14怎麼也連到這題來了?