2 jijing questions

brigittew

54.一东东的价格为p，先下降了x percent(注意是x%,不是x),后下降2x percent,问最后价格，用p表示：
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P*(100-x)(100-2x)/10000

why not p(1-x)(1-2x), since here the question is to get the final price, and x here express the percentage?

24. 此题是我数学的最后一道,花了我最后5分钟.实在是理解有问题,最后选的答案竟然和我自己的答案还是不一样,请大家讨论吧.这到数学怎么和阅读有一拼.
From the beginning of last year, Price per share increased K percent. Earning per share increased M percent. Question: ask the ratio in percentage for price per share to earning per share in increase. In term of K, M.
[确认](K-M)/(100+M)。此题是一老JJ

i calculated it for near half an hour, however i cant get any expression like the above, can anyone tell me the detailed method used here?

thanks in advance

brigittew

i see, thanks so much!!

tongxun

同意！以后我就用你的方法！谢谢。

skycrash

why not make life easy. don't need always use the standard way.

tongxun

bigittew:
54、题目已经说明了X 是剔除了百分比后的数字，比如75%，X=75，所以是100-75，而不是1-75
24、[x(1+k%)/y(1+m%) - x/y]/(x/y)

skycrash

24. the easy way.
suppose the original price is 100.so after increase,
price per share is 100(1+k/100)=100+k
earning per share is 100(1+M/100)=100+m
so the result is (100+k-100-m)/(100+m)=(k-m)/(100+m)
half an hour, sorry, I think you make a spelling mistake, half a min, right?