Board logo

标题: 求助一道gwd5-28 [打印本页]

作者: liuxiaolan89    时间: 2006-5-31 15:15     标题: 求助一道gwd5-28

Q28:

This year Henry will save a certain amount of his income, and he will spend the rest. Next year Henry will have no income, but for each dollar that he saves this year, he will have 1 + r dollars available to spend. In terms of r, what fraction of his income should Henry save this year so that next year the amount he was available to spend will be equal to half the amount that he spends this year?

A. 1/(r+2)

B. 1/(2r+2)

c. 1/ (3r+2)

D. 1/(r+3)

e. 1/(2r+3)

I have no idea....please help me, thanks.


作者: longxiaomeim    时间: 2006-5-31 20:55

设今年收入为R,储蓄比率是x,则今年的支出为R(1-x),储蓄为Rx,明年的储蓄总额为R*x*(1+r), 则有等式R*x*(1+r)=0.5*R*(1-x),化简得x=1/(3+2r)
作者: dbearwangs    时间: 2006-6-2 21:22

同意2楼的 关键是设定储蓄比率fraction of his income
作者: missouyang    时间: 2006-6-4 19:54

but for each dollar that he saves this year, he will have 1 + r dollars available to spend.

我竟然把这句话理解成第二年,他又1+r这么多钱可以花。。。。


作者: liuxiaolan89    时间: 2006-6-5 07:02

thanks  a  lot  !!!!!!




欢迎光临 国际顶尖MBA申请交流平台--TOPWAY MBA (http://forum.topway.org/) Powered by Discuz! 7.2