来自《耶鲁大学开放课程：金融理论 第7集 第7集》

• 
  
  Yep?
  多少
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  Student: 150 bucks.
  学生 150美元
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  It is, and how did you get that?
  说对了 怎么算出来的呢
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  Student: The doubling rule at 6 percent interest
  学生 在利率为6%时根据翻倍法则
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  it takes 12 years to double your money
  12年存款能够翻倍
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  so in 24 years you're going to quadruple your money.
  因此24年就能翻四倍
• 
  
  So then you just put that 4 into the equation.
  把4带到公式里面去
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  So it's 1 - 1 quarter, so that's 3 quarters,
  就是1-1/4 也就是3/4
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  and 3 quarters times the 200 we got before is 150, exactly.
  3/4乘以200正好得到150
• 
  
  Exactly right what he said.
  他说的非常对
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  So does everybody get that?
  大家都明白了吗
• 
  
  Let's try another one.
  我们再做一个例子