It takes 9 hours for a bus to go from A to B, and 15 hours for a truck. Now the two cars start at the same time and drive opposite each other. How many hours later will the two cars meet?
从甲地到乙地客车要行9小时，货车要行15小时．现在两车同时出发，相对而行，经过几小时后两车相遇？
<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/9) + (1/15)</gadget>
<output>8/45 = around 0.177778</output>

<gadget id="calculator">1 / (8/45)</gadget>
<output>45/8 = around 5.625</output>

<result>45/8 = around 5.625</result>