There is such a fraction, its product with 5 (5/6) is an integer, its quotient with (10/21) is also an integer, what is the smallest of such fractions?
有这样一个分数，它与5(5/6)的积是一个整数，它与(10/21)的商也是一个整数，这样的分数中最小的一个是多少．
<gadget id="calculator">30 / 7</gadget>
<output>30/7 = around 4.285714</output>

<result>30/7 = around 4.285714</result>