帮忙过来看看呀~GWD-29-35(搜过没有的)

幽幽sally

In Patton City, days are categorized as having heavy rainfall (more than two inches), moderate rainfall (more than one inch, but no more than two inches), light rainfall (at least a trace, but no more than one inch), or no rainfall.  In 1990, there were fewer days with light rainfall than in 1910 and fewer with moderate rainfall, yet total rainfall for the year was 20 percent higher in 1990 than in 1910.（是什么意思啊？是它的amount of rainfall?）

If the statements above are true, then it is also possible that in Patton
                        City
                    

1. the number of days with heavy rainfall was lower in 1990 than in 1910(不知道怎么看)
                               

2. the number of days with some rainfall, but no more than two inches, was the same in 1990 as in 1910  应该是少
                               

3. the number of days with some rainfall, but no more than two inches, was higher in 1990 than in 1910应该是少
                               

4. the total number of inches of rain that fell on days with moderate rainfall in 1990 was more than twice what it had been in 1910不能确定是怎么样
                               

5. the average amount of rainfall per month was lower in 1990 than in 1910(不知道怎么看)

答案是Ａ

 

幽幽sally

又搜了下。 ..貌似找到了~

呵呵~不好意思拉

uibewsj

我先自己推了下：

1990 和1910年均有H,M,L,N四种关于雨水的天气情况。
1990年下三种雨的天数分别为H1，M1，L1
1910年下三种雨的天数分别为H0，M0，L0
根据In 1990, there were fewer days with light rainfall than in 1910--->L1<L0        (1)
根据
                In 1990, there were fewer days with moderate rainfall (than in 1910)---->M1<M0    (2)
根据total rainfall for the year was 20 percent higher in 1990 than in 1910---->H1+M1+L1=1.2(H0+M0+L0)  (3)
综合(1),(2),(3)，得出：
1.2(H0+M0+L0)<H1+M0+L0
1.2H0+0.2(M0+L0)<H1
故H0<H1 (A)

FlowerJay

the number of days with heavy rainfall was lower in 1990 than in 1910

按照楼上的说，好像应该是H1<H0

uibewsj

我晕！原来是犯了把降雨量看成降雨天数的错误！

其实，人家问的是哪一种有可能, 而且多于2到无穷 inches的都算大雨,要达到一定量，天数多少都可能。往下第一个就看到选项A，选就是了，都不用看别的。遇到这种题真是想得越简单越赚！

最复杂的做法：
1990 和1910年均有H,M,L,N四种关于雨水的天气情况。

1910年下三种雨的天数分别为H0，M0，L0

1990年下三种雨的天数分别为H1，M1，L1

根据In 1990, there were fewer days with light rainfall than in 1910--->L1<L0        (1)

根据 In 1990, there were fewer days with moderate rainfall (than in 1910)---->M1<M0    (2)

根据total rainfall for the year was 20 percent higher in 1990 than in 1910---->aH1+bM1+cL1=1.2(dH0+eM0+fL0)  (3)
                 其中

a,b,c,d,e,f分别为各种雨天分别平均一天的降雨inch数

因为M1,M0均为中雨天数，而中雨在1与2之间，所以1<b,e<2àb<2e (4)

 

   A. the number of days with heavy rainfall was lower in 1990 than in 1910 对

   B. the number of days with some rainfall, but no more than two inches, was the same in 1990 as in 1910   错，因为(1)+(2)àM1+L1<M0+L0

   C. the number of days with some rainfall, but no more than two inches, was higher in 1990 than in 1910  错，因为(1)+(2)àM1+L1<M0+L0

   D. the total number of inches of rain that fell on days with moderate rainfall in 1990 was more than twice what it had been in 1910  错，由(2),(4)àbM1<2*eM0

   E. the average amount of rainfall per month was lower in 1990 than in 1910 错，由(3)à (aH1+bM1+cL1)/12=1.2(dH0+eM0+fL0)/12=(dH0+eM0+fL0)/10>(dH0+eM0+fL0)/12

故(aH1+bM1+cL1)/12>(dH0+eM0+fL0)/12

FlowerJay

呵呵，楼上正解！这破题难得可以！主要难点在于 aH0 和 bH1; 以及cM0 和 dM1的关系。 因为heavy rain的系数可以是>>2， 而c,d的范围是 1< <2 ， 所以D中的more than twice是不可能出现的。我觉得这种东西一定要5，6分钟才能想到了。考试时候遇到基本就是蒙了就过了

幽幽sally

对呀...考试的时候都凭感觉做的说~

hedge

thanks

panglin

thx . like it

fd983314

the number of days.....还没在这种地方栽过，老了。。。。

[此贴子已经被作者于2007-1-21 15:40:04编辑过]