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标题: A DS question [打印本页]

作者: sunnyfields    时间: 2007-7-8 07:21     标题: A DS question

Hi, all, i am stuck with a DS problem and hope anyone can give me some feedbacks, thanks.:

23. If n is an integer between 2 and 100 and if n is also the square of an integer, what is the value of n?

(1) n is the cube of an integer.

(2) n is even.

the solution is A , but i don't get it. 


作者: quejingui77    时间: 2007-7-8 20:48

我也在练习中,所以我说我的想法,有误的话请指较。

题目已有的条件为:n is an integer between 2 and 100 and if n is also the square of an integer

所以可以推数字必定落在这个范围中

2*2=4

3*3=9

4*4=16

5*5=25

6*6=36

7*7=49

8*8=64

9*9=81

10*10=100

(A)选项条件,n is the cube of an integer.一样类推

2*2*2=8

3*3*3=27

4*4*4=64

如果这题直接从(A)推立方数在2~100之间的,并且此数字也可以是某数的平方,应该会是最快判断出条件上可不可以充分。


作者: sunnyfields    时间: 2007-7-9 06:26

Thank you very much, appreciated it.


作者: XIHUAII    时间: 2007-7-21 00:48

100以内是一个数立方的只有2-4,只有4^3=64是8的平方,所以OK
作者: tjbian78    时间: 2007-7-28 15:45

QUOTE:
以下是引用XIHUAII在2007-7-21 0:48:00的发言:
100以内是一个数立方的只有2-4,只有4^3=64是8的平方,所以OK

不错,思路很妙!






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