It is known that the distance between A and B is 30 kilometers. If A and B start from A and B at the same time and go in the same direction, A’s speed is 15 km/h, and B’s speed is 10 km/h. How many hours does it take for A to catch up with B?
已知A、B两地相距30千米，如果甲、乙分别从A、B两地同时出发同向而行，甲的速度是15千米/时，乙的速度是10千米/时，则甲追上乙需经过多少小时
<gadget id="calculator">15 - 10</gadget>
<output>5</output>

<gadget id="calculator">30 / 5</gadget>
<output>6</output>

<result>6</result>