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【OG20-P166-131题】
Alex deposited x dollars into a new account that earned 8 percent annual interest, compounded annually. One year later Alex deposited an additional x dollars into the account. If there were no other transactions and if the account contained w dollars at the end of two years, which of the following expresses x in terms of w?
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题目:Alex在一个新账户里存了x美元,每年的利率是8%,一年以后他又另外在账户里面存了x美元。假设没有其他交易,两年后账户余额为w美元,问用w表示x的式子是哪一个。
解:第一年结束后账户余额为x(1+8%)=1.08x;第二年又存了x美元,也就是本金变为1.08x+x,因此第二年结束时账户余额为(1.08x+x)(1+8%)=(1.08+1.082)x=w,因此x=w/(1.08+1.082).
题目讨论 (3条评论)

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414617qqin
我把2.08*1.08给算出来了,多此一举
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0 回复 2021-07-26 16:21:01
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你这只猪
列方程的时候差点写成2.08,到时候更难算了
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0 回复 2020-06-17 11:22:26
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感觉自己萌萌哒
第一年结束本息时为:x(1+0.08),第二年再存入x,第二年本金为:x(1+0.08)+x;
第二年结束时本息为:[x(1+0.08)+x](1+0.08)=w;
解方程:1.08x+x=w/1.08
x(1.08+1)=w/1.08
x=w/1.08(1.08+1)
x=w/[(1.08)^2+1.08],选D0
0 回复 2015-12-01 11:30:38