The denominator of a fraction is expanded to 4 times of the original, and the numerator is reduced to (1/3) and then becomes (13/60). What is the original fraction?
一个分数的分母扩大到原来的4倍，分子缩小到原来的(1/3)后是(13/60)，这个分数原来是多少．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">13 / (1/3)</gadget>
<output>39</output>

<gadget id="calculator">60 / 4</gadget>
<output>15</output>

<gadget id="calculator">39 / 15</gadget>
<output>13/5 = around 2.6</output>

<result>13/5 = around 2.6</result>