Answers

2016-07-16T11:53:21+08:00
Given : 

           a_{1}=1, a_{4}= \frac{1}{125}, r=?

Solve it using the geometric sequence formula,
 
           a_{n}=a_{1}r^{n-1}
            \frac{1}{125}=1r^{4-1}
            \frac{1}{125}=r^3
            \frac{1}{5}=r

So, the common ratio is  \frac{1}{5}
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