A train travels from place A to place B, which is 720 kilometers away, and travels 180 kilometers in 3 hours. According to this calculation, how many hours will it take for the train to reach place B?
一列火车从甲地开往相距720千米的乙地，3小时行了180千米，照这样计算，这列火车再行几小时就可以到达乙地呢？
<gadget id="calculator">180 / 3</gadget>
<output>60</output>

<gadget id="calculator">720 / 60</gadget>
<output>12</output>

<gadget id="calculator">12 - 3</gadget>
<output>9</output>

<result>9</result>