A fraction can be divided into (3/7) by adding 3 to its numerator, and can be divided into (2/5) by subtracting 2 from its denominator. What is the fraction?
一个分数，它的分子加上3可约分为(3/7)，它的分母减去2可约分为(2/5)，这个分数是多少．
<gadget id="calculator">30 / 77</gadget>
<output>30/77 = around 0.38961</output>

<result>30/77 = around 0.38961</result>