It takes 6 hours for a passenger car to go from station A to station B, and it takes 3 hours for a car to go from station B to station A. The two cars start at the same time. How many hours later will they meet?
一辆客车从A站开往B站，需要6小时，一辆轿车从B站开往A站需要3小时，这两辆车同时出发，几个小时后，它们会相遇？
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/6) + (1/3)</gadget>
<output>1/2 = around 0.5</output>

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

<result>2</result>