返回列表 发帖

请教800SCORE中的第一套题中的一个数学问题

Question # 10, your answer = E If 4 students were added to a dance class, would the teacher be able to divide her students evenly into a dance team (or teams) of 8?

(1) If 12 students were added, the teacher could put everyone in teams of 8 without any leftovers.

(2) The number of students in the class is currently not divisible by 8.

A) Statement (1) BY ITSELF is sufficient to answer the question, but statement (2) by itself is not.

B) Statement (2) BY ITSELF is sufficient to answer the question, but statement (1) by itself is not.

C) Statements (1) and (2) TAKEN TOGETHER are sufficient to answer the question, even though NEITHER statement BY ITSELF is sufficient.

D) Either statement BY ITSELF is sufficient to answer the question.

E) Statements (1) and (2) TAKEN TOGETHER are NOT sufficient to answer the question, meaning that further information would be needed to answer the question.

(A) To divide the class evenly into teams of 8, we would need the class to have a number of students that is a multiple of 8.

One way to think about Statement 1 is to think of 12 as 8 + 4, meaning that if you add 8 and then 4, you are really adding a full team of 8 and four more people, which is what the question asks. That will only help you make even teams if you don't already have even teams.

Another way is to use numbers: If you start with 4 people in the class and add 12, you have a class of 16 people, which can be split evenly into teams of 8.

Adding 12 is the same as adding 4, because 12 is 8 + 4. For example, if there were 4 people at the start and 4 were added, it would make an even 8. If 12 were added, it would make 16, which is also evenly divisible. Thus, Statement 1 must be sufficient because it shows that if you add 12 people to a class you get an even number, then the class COULD NOT HAVE BEEN EVEN IN THE FIRST PLACE. Eliminate answer choices BCE, which require 1 not to be sufficient.

Statement 2 doesn't tell you anything that will let you know if the teams are evenly divisible. Since this does not answer the question, the answer to the question is A., only statement 1 is sufficient.

我个人认为如果是加12个的话,如果我八个team里面有一个组就少12个人,那么四个人加进去怎么也不会平均的不知道我理解对不对

收藏 分享

答案是A。问:加入4个人,是否能平均分成8组?

1、加入12个人,能平均分为八组!

2、当前的人数不能平均分为8组!

设原来人数为X,问题是x是否被8整除?条件1:x+12=8n-->x+4=8(n-1)能被8整除

条件2:带入法,x=8n+4时候,x+4能被8整除,X不等于8n+4时候,x+4不能被8整除。

TOP

返回列表

站长推荐 关闭


美国top10 MBA VIP申请服务

自2003年开始提供 MBA 申请服务以来,保持着90% 以上的成功率,其中Top10 MBA服务成功率更是高达95%


查看