Two warships departed from two ports 609 kilometers apart at the same time. One warship traveled 42 kilometers per hour, and the other warship traveled 45 kilometers per hour. How many hours did it take to meet?
两艘军舰从相距609千米的两个港口同时相对开出，一艘军舰每小时行42千米，另一艘军舰每小时行45千米，经过几小时相遇？
<gadget id="calculator">42 + 45</gadget>
<output>87</output>

<gadget id="calculator">609 / 87</gadget>
<output>7</output>

<result>7</result>