模考了下,数学2道题没弄明白,帮忙看看

sophialj

A certain liabarary assess fines for overdue books as follows:

On the first day that a book over due, the total fine is 0.1 USD; for each additional day that the book is over due, the total fine is either increased by USD0.3 or doubled, whichever results in a lesser amount.

What is the total fine for a book on the 4th day it is over due?

A) 0.6 B)0.7 C)0.8 D)0.9 E)1     答案选0.7 我选0.8

Table:
 
Stock     Number of shares
V              68
W            112
X               56
Y              94
Z               45
 
The table shows the number of shares of each of the 5 stocks owned by Mr.Sami. If Mr.Sami was to sell 20 shares of stock X and buy 24 shares of stock Y, what would be the increase in the range of the numbers of shares of the 5 stocks owned by Mr.Sami?
 
A) 4  B) 6 C)9 D)15 E)20     答案是15,没搞懂

[此贴子已经被作者于2009-6-23 16:15:34编辑过]

loire_zhang

我也没搞懂，希望高手指教

wannacharge

刚注册，我能回答么？

sophialj

太能了,回答吧

wannacharge

1、第一天 0.1  第二天 0.2  第三天 0.4  第四天 0.7

2、(112-45)-[(94+24)-(56-20)]=15

sophialj

同学我看懂第一个了,还是你思维比较活跃,我怎么没想到可以2种同时采用呢,谢谢了

第二题还是没太搞懂,你能解释下你理解的问题意思吗??我没看懂你的式子,谢谢了

wannacharge

没买卖之前是112-45。

买卖之后：份数最高的是96+24  最少的是56-20.

增加的份数是差值。

sophialj

大概明白你意思了,谢谢了