两道PREP的数学题，大家能帮我解答下么

chelly

第一题

before being simplified ,the instructions for computing income tax in country R
        were to add 2% of one's annual income to average (算术平均数) of 100 units of country R'  currency and 1% of one's annual income . which of the following represnets thr simplified formula for computing the income tax, in country R's  currency, for a person in that country whose annual income is I ?

A.50+I/200     B. 50+3I/100    C. 50+I/40    D.    100+I/50     E.100+3I/50  

答案是C  有谁能解释下红色的那句话是什么个意思啊

第二题

STOCK         Number of share
  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. Samsi. if MR. Samsi 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. Samsi

A  4       B  6       C   9          D   15        E  20

答案是 D

[此贴子已经被作者于2009/10/11 21:56:24编辑过]

chelly

自己顶下~~~麻烦知道的留个脚印哦~~偶16号就考试了~~急啊

coolboxer

第一题等大牛吧。

第二题，就是把之前的range:67减去之后的range:82。

huster

把and的两边的值加起来除以二          这就是average的意思

chelly

灰常感谢~~原来range是这个意思