Car A travels from point A to point B and can arrive there in 6 hours; car B drives from point B to point A in 9 hours. Two cars leave at the same time, how many hours will they meet?
甲车从A地开往B地，6小时可以到达；乙车从B地开往A地，9小时可以到达．两车同时开出，几小时会相遇？
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">(1/6) + (1/9)</gadget>
<output>5/18 = around 0.277778</output>

<gadget id="calculator">1 / (5/18)</gadget>
<output>18/5 = around 3.6</output>

<result>18/5 = around 3.6</result>