2006年12月math原始机经讨论稿2（更新到50题，见4楼，12.05更新）

zhangxiaofff

            

44.set 【数】集(合), 族, 系(统)X has 5 numbers, and the average is greater than medium中间的, 中等的； set Y has 7 numbers, and the average is greater than medium （median）. set Z combined x and y, is the average greater than medium?

(1) medium of set X is greater than medium of set Y

(2) average of set X is greater than average of set Y

答案：B（欢迎讨论）

This is my analysis:

A: the average of X.
B:the average of Y.

Z: the average of Z.

a: the medium of X.

b: the medium of Y.

z: the medium of Z.

 

according to (1): we get a>z>b (a>b，对于集合Z来说，那么比a大的最多5个，所以z<a；同样，比b小的最多5个，所以z>b。)  

▲▲▲●●☆★▲▲▲●●   （中间分别为a和b）可以理解了吧

according to (2): 5A+7B=12Z,we get A>Z>B  自己列不等式算一下就好了

A>a  ， B>b

But we do not know if B>a, or if A>b.

so we can not get a solution. the correct selection is (E)

But if (1) is changed to a<b, and (2) remain unchanged, we get:

a<z<b,   A>Z>B, and A>a ，B>b, so the outcome is Z>z.

If (2) is changed to A<B, and (1) remain unchanged. We get:

a>z>b, A<Z<B, and A>a, A>a，so the outcome is Z>z

 把前面朋友的答案稍微再加解释一下，希望帮助大家理解

 把前面朋友的答案稍微再加解释一下，希望帮助大家理解

zhangxiaofff

汗，看讨论稿真的受益很多，但是比较花时间，我做了比较完整的，蛮搅传上来大家分享，这样一目了然

bennynkp

21.3X-2Y=32, 根号下3X+根号下2Y=4 求X-Y?

A 4, B 8 ,C 10  ,D 12...

答案：10（题目应该是根号下3X-根号下2Y=4

Any one can help to explain this? I am going to exam tmr........

camilla78

为什么没人 讨论第42题呢？？？求助！！！

camilla78

48题答案到底是什么啊

linpeitzu

48题为什麽知道高就可以推得AB的距离
只知道高=30，
AB可以等於80也可以等於120吧
那这样不就不行了？
我觉得答案还是B

panglin

Can somebody expalin question 49? thanks!!!!

hello55olleh

44.set X has 5 numbers, and the average is greater than medium; set Y has 7 numbers, and the average is greater than medium. set Z combined x and y, is the average greater than medium?

(1) medium of set X is greater than medium of set Y (2)average of set X is greater than average of set Y

答案：B（欢迎讨论）

这里，为什么是B呀？NN指点呀

48.画图题，只能描述一下了。就是有一段圆弧，是高尔夫球的飞行线路，A，B是弧形与地面的交点，C是弧顶。AB=BC，问飞行的距离是否超过100。
                        

（1）C距地面...（没用）（2）AB=50 

答案：B（DS题）

这个1）怎么不可以呢？题目求的是弧的长度，只要知道半圆的半径就好。C距地面多少多少，距离不就是半径吗？因为C的弧顶。。。。

不知道，觉得是D似的。。。NN指点

hello55olleh

以下是引用zhangxiaofff在2006-12-14 15:47:00的发言：

   

44.set 【数】集(合), 族, 系(统)X has 5 numbers, and the average is greater than medium中间的, 中等的； set Y has 7 numbers, and the average is greater than medium （median）. set Z combined x and y, is the average greater than medium?

(1) medium of set X is greater than medium of set Y

(2) average of set X is greater than average of set Y

答案：B（欢迎讨论）

This is my analysis:

A: the average of X.
B:the average of Y.

Z: the average of Z.

a: the medium of X.

b: the medium of Y.

z: the medium of Z.

 

 

according to (1): we get a>z>b (a>b，对于集合Z来说，那么比a大的最多5个，所以z<a；同样，比b小的最多5个，所以z>b。)  

▲▲▲●●☆★▲▲▲●●   （中间分别为a和b）可以理解了吧

according to (2): 5A+7B=12Z,we get A>Z>B  自己列不等式算一下就好了

A>a  ， B>b

But we do not know if B>a, or if A>b.

so we can not get a solution. the correct selection is (E)

But if (1) is changed to a<b, and (2) remain unchanged, we get:

a<z<b,   A>Z>B, and A>a ，B>b, so the outcome is Z>z.

If (2) is changed to A<B, and (1) remain unchanged. We get:

a>z>b, A<Z<B, and A>a, A>a，so the outcome is Z>z

 把前面朋友的答案稍微再加解释一下，希望帮助大家理解

 把前面朋友的答案稍微再加解释一下，希望帮助大家理解

我觉得这题目是E啊。。。。指点把

hello55olleh

顶顶顶....呼唤N人,上面两道疑问