PREP Math & CR真心求解！！哪位大牛出手相助？

Wendy322

划线的是答案！LZ完全找不到思路！虚心求教！
Math
Beforebeing simplified, the instructions for computing income tax in Country R wereto add 2 percent of one's annual income to the average (arithmetic mean) of 100units of Country R's currency and 1 percent of one's annual income.  Which of the following represents thesimplified formula for computing the income tax, in Country R's currency, for aperson 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/100)CR
1) Followingseveral years of declining advertising sales, the Greenville Times reorganizedits advertising sales force two years ago. Before the reorganization, the sales force was organized geographically,with some sales representatives concentrating on city-center businesses andothers concentrating on different outlying regions.  The reorganization attempted to increase thesales representatives’ knowledge of clients’ businesses by having each salesrepresentative deal with only one type of industry or of retailing.  After the reorganization, advertising salesincreased.
In assessing whether theimprovement in advertising sales can properly be attributed to thereorganization, it would be helpful to find out each of the following EXCEPT:
A. Two years ago, what proportionof the Greenville Times’s total revenue was generated by advertising sales?
B. Has the circulation of theGreenville Times increased substantially in the last two years?

C. Has there been a substantialturnover in personnel in the advertising sales force over the last two years?

D. Before the reorganization, hadsales representatives found it difficult to keep up with relevant developmentsin all the types of businesses to which they were assigned?
E. Has the economy in Greenvilleand the surrounding regions been growing rapidly over the last two years?
2) Althoughfullerenes--spherical molecules made entirely of carbon--were first found inthe laboratory, they have since been found in nature, formed in fissures of therare mineral shungite.  Since laboratorysynthesis of fullerenes requires distinctive conditions of temperature andpressure, this discovery should give geologists a test case for evaluatinghypotheses about the state of the Earth's crust at the time these naturallyoccurring fullerenes were formed. Which of the following, iftrue, most seriously undermines the argument?
(A) Confirming that theshungite genuinely contained fullerenes took careful experimentation.

(B) Some fullerenes havealso been found on the remains of a small meteorite that collided with aspacecraft.
(C) The mineral shungiteitself contains large amounts of carbon, from which the fullerenes apparentlyformed.

(D) The naturallyoccurring fullerenes are arranged in a previously unknown crystallinestructure.
(E) Shungite itself isformed only under distinctive conditions.

kexin2008

那道数学题在manhattan的论坛上的解释为：
Let’s break that down into separate steps:
“add 2 percent of one’s annual income to” the next thing
“average (arithmetic mean) of 100 units of country R’s currency and 1 percent of one’s annual income”
The average of 100 and 1 percent of R is (100 + 0.01R)/2. (The standard average formula is: average = sum / # of things.)
Then, what was that other part? Oh, yes, “add 2 percent of one’s annual income.” So that’s 0.02R and I should add it to my average above. That gives me:
0.02 R + (100+0.01 R)/2
Now I have to simplify this thing. I can split the right-hand term into two parts:
0.02 R + (100/2) + (0.01 R /2)
2R/100 + 50 + R /(100*2) = 2R /100 + 50 + R /200 = 4R /200 + 50 + R /200=
5R /200 + 50 = R /40 + 50

Wendy322

谢谢你的答案，超级详细啊～～原来我连题目都没看明白呀～～～惭愧