1956 AMC 12 第 4 题
先试着解答 1956 AMC 12 第 4 题，然后核对你的答案与精心整理的解答，解答来自 LIVE by Po-Shen Loh。你也可以参加完整限时模拟考试、查看全部 1956 AMC 12 解答，或核对答案。
所有题目均经美国数学协会（MAA）官方合法授权使用。
4.
一名男子有 可供投资。他将 按 的利率投资，又将 按 的利率投资。为了获得每年 的收入，他必须将余款按下列利率投资：
A man has to invest. He invests at and at In order to have a yearly income of he must invest the remainder at:
答案：E
小提示：
先求尚未投资的本金和仍需获得的收入
First find both the uninvested principal and the income still needed
大提示：
前两笔投资每年分别获得 和
The first two investments earn and per year
解答：
剩余可投资金额为 前两笔投资获得 美元，所以余款必须获得 美元。所需利率为
因此，正确答案是 E。
The amount left to invest is The first two investments earn dollars, so the remaining investment must earn dollars. Its required rate is
Thus, the correct answer is E.
其他年份的第 4 题
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