又来请教大神数学题了。。。。

whisper15

1. year the price per share of Stock Xincreased by k percent and the earnings per share of Stock Xincreased by m percent, where k is greater than m.  By what percent did the ratio of price pershare to earnings per share increase, in terms of k and m?

A.   K/M%

B.    (k – m) %

C.   [100(k – m)] / (100 + k) %

D.  [100(k – m)] / (100 + m) %

E.    [100(k – m)] / (100 + k + m) %

怎么能化简得到D呀。。。。

2.

If n = 3k, is k aninteger?

(1)             n is an integer.

(2)             n/6 is an integer.

                                                                                                                              

A. Statement (1) ALONE issufficient, but statement (2) alone is not sufficient.

B.Statement (2) ALONE is sufficient, but statement (1) alone is notsufficient.

C. BOTH statements TOGETHERare sufficient, but NEITHER statement ALONE is sufficient.

D.EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHERare NOT sufficient.YOULAI

楼主学渣。。死都想不明白为什么A单独不可以。。如果不能整除，3不是不能被除尽的吗。。。。

gurui826

n=2 k= 2/3 n=3 k=1

mylingking

第二题A选项 若n=1, 则k＝三分之一；若n＝3，K＝1

mylingking

第一题 设original price为x，original earnings为y
original ratio＝x/y

now, price=x(1+K/100); earnings=y(1+m/100)

the ratio now＝上面的price除以earnings

然后increase就是上一步得出的ratio减去x/y

后面的我不知道怎么在这上面打出来了，太多分数，思路是根据以上的信息求出（change of ratio/original ratio）*100 反正化简后就得出D