数学请教谢了

ypl214 · 发表于 2010-7-26 16:12:43

1On Saturday morning, Malachi will begin a camping vacation and he will return home at the end of the first day on which it rains.If on the first three days of the vacation the probability of rain on each day is 0.2, what is the probability that Malachi will return home at the end of the day on the following Monday?

A.0.008

B.0.128 correct
C.0.488

D.0.512

E.0.640
Last year the price per share of Stock X increased by k percent and the earnings per share of Stock X increased by m percent, where k is greater than m.By what percent did the ratio of price per share 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) %correct

E.[100(k-m)]/(100+k+m) %

Last year the price per share of Stock X increased by k percent and the earnings per share of Stock X increased by m percent, where k is greater than m.By what percent did the ratio of price per share 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) %correct

E.[100(k-m)]/(100+k+m) %

maggie520 · 发表于 2010-7-26 16:22:15

第一题有saturday, sunday, monday. 每天下雨的概率是0.2, 如果这天下雨了，那他当天就会回来。
所以如果要monday才回来，那么周六周日都不能下雨，因此0.8x0.8x0.2=0.128

maggie520 · 发表于 2010-7-26 16:26:05

D.[100(k-m)]/(100+m) %correct

设price=P。 earning=e。
原来的比值是P。/e。x100%
新的比值是 [(P。(100+k)%) / (e。(100+m)%) ] - [(P。/e。)x100%]
然后再除以原比值 P。/e。
最后化简就是答案D

ypl214 · 发表于 2010-7-26 17:23:56

多谢了

数学请教谢了

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数学 请教 谢了

所属分类: GMAT考试

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数学请教谢了