A train of passenger cars and a train of trucks depart from A to B at the same time. It takes 5 hours for the bus to complete the journey, and 7 hours for the truck to complete the journey. When the bus travels halfway, what fraction of the journey does the truck travel?
一列客车和一列货车同时从甲地出发开往乙地，客车行完全程要5小时，货车行完全程要7小时．当客车行完全程的一半时，货车只行了全程的几分之几？
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/2) / (1/5)</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">(1/7) * (5/2)</gadget>
<output>5/14 = around 0.357143</output>

<result>5/14 = around 0.357143</result>