A fraction is multiplied by (2/3) and (4/7) respectively, the sum of the two products is (13/14), what is the fraction.
一个分数分别与(2/3)，(4/7)相乘，两个积的和是(13/14)，这个分数是多少．
<gadget id="calculator">13 / 14</gadget>
<output>13/14 = around 0.928571</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">(2/3) + (4/7)</gadget>
<output>26/21 = around 1.238095</output>

<gadget id="calculator">(13/14) / (26/21)</gadget>
<output>3/4 = around 0.75</output>

<result>3/4 = around 0.75</result>