It takes 8 hours for a passenger car to drive from Wuping to Fuzhou, and 10 hours for a truck to drive from Fuzhou to Wuping. The two cars leave from Wuping and Fuzhou at the same time, and drive towards each other. How long can they meet each other?
一辆客车从武平开往福州要8小时，货车从福州开往武平要10小时，两车同时从武平、福州两城开出，相向而行，几小时可以相遇？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/8) + (1/10)</gadget>
<output>9/40 = around 0.225</output>

<gadget id="calculator">1 / (9/40)</gadget>
<output>40/9 = around 4.444444</output>

<result>40/9 = around 4.444444</result>