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这题JJ答案是?? 急啊!!

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楼主
发表于 2008-2-2 20:54:00 | 只看该作者

这题JJ答案是?? 急啊!!

95.       Set A has n integers. Arithmetic mean is m. standard deviation is R.   Set B has all the elements of A  and  x.  if  standard deviation of B is r ,   is r < R? 
(1) x = m 
(2) m <= x <= m+R

请帮我确认这题答案??

D or A??

 

108.  one man drives from west to east. He saw the mile marker of 88. the number 88 has the property, like 484 and 57475, when you reverse the number, it appears to be the same. Then that man drives the other 2 hours at the speed of 70 mile per hour. How many numbers that he would see will possess that property.
                

72*2+88=144+88=232
                

88232之间有多少个这类数(不包括88):99101111121131141151161171181191202212222。共14个。
            

 KEY14  

这题到底在说甚么啊??  为什么88232不算??

 

149.       (2,3) y轴多远
            

根号(3-0)^2=3
                

KEY3
                

这题不是很明显点(2,3)是距离2??  怎么解释呢??

沙发
发表于 2008-2-2 22:43:00 | 只看该作者
149 如果题目你没有说错 (2,3)点到y轴的距离就是2
板凳
发表于 2008-2-2 22:53:00 | 只看该作者

95

D吧

地板
发表于 2008-2-2 23:01:00 | 只看该作者
以下是引用ken92在2008-2-2 20:54:00的发言:

95.       Set A has n integers. Arithmetic mean is m. standard deviation is R.   Set B has all the elements of A  and  x.  if  standard deviation of B is r ,   is r < R? 
(1) x = m 
(2) m <= x <= m+R

请帮我确认这题答案??

D or A??

 

 

108.  one man drives from west to east. He saw the mile marker of 88. the number 88 has the property, like 484 and 57475, when you reverse the number, it appears to be the same. Then that man drives the other 2 hours at the speed of 70 mile per hour. How many numbers that he would see will possess that property.
    

72*2+88=144+88=232
    

88232之间有多少个这类数(不包括88):99101111121131141151161171181191202212222。共14个。
   

 KEY14  

这题到底在说甚么啊??  为什么88232不算??

 

 

149.       (2,3) y轴多远
   

根号(3-0)^2=3
    

KEY3
    

这题不是很明显点(2,3)是距离2??  怎么解释呢??

149,题目已更正,答案是2

108,题目已更正,不包括88,但包括232,因为题目说the other 2 hours

95,D

5#
发表于 2008-2-3 10:30:00 | 只看该作者
以下是引用macelino在2008-2-2 23:01:00的发言:

149,题目已更正,答案是2

108,题目已更正,不包括88,但包括232,因为题目说the other 2 hours

95,D

108怎么变成72*2了?不是70*2+88么

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