马上要考了,求问两道prep题,多谢大家了

lijia1301981 · 发表于 2008-11-18 00:25:00

At a dinner party, 5 people are to be seated around a circular table. Two seating arrangements are considered different only when the positions of the people are different relative to each other. What is the total number of different possible seating arrangements for the group?

(A) 5

(B) 10

(C) 24

(D) 32

(E) 120

答案:C

When a certain tree was first planted, it was 4 feet tall, and the height of the tree increased by a constant amount each year for the next 6 years. At the end of the 6th year, the tree was 1/5 feet taller than it was at the end of the 4th year. By how many feet did the height of the tree increase each year?

答案是2/3, 大家知道是怎么算出来的吗?

timego · 发表于 2008-11-18 00:36:00

[此贴子已经被作者于2008-11-18 0:36:30编辑过]

SH简单 · 发表于 2008-11-18 01:23:00

第一题我没有很简单的办法,只有想每5个人的排列,都有平移的可能,根据题意,就不是不同的排列了,并且可以平移5次

比方说

a b c d e

e a b c d

d e a b c

c d e a b

b c d e a

都是同一种排列,5 种方式

所以计算方法是(5*4*3*2*1) / 5, 答案是24

第二题楼主的条件给错了,我算了一下

条件应该是:When a certain tree was first planted, it was 4 feet tall, and the height of the tree increased by a constant amount each year for the next 6 years. At the end of the 6th year, the tree was 1/5 taller than it was at the end of the 4th year. By how many feet did the height of the tree increase each year?

(4+6x)/(4+4x) = 6/5 x = 2/3

[此贴子已经被作者于2008-11-18 1:23:46编辑过]

lijia1301981 · 发表于 2008-11-18 10:26:00

明白了,多谢哈!!

马上要考了,求问两道prep题,多谢大家了

马上要考了,求问两道prep题,多谢大家了

所属分类: GMAT考试

正在浏览此版块的会员 ()

浏览过的版块