The waterworks injects water into an empty reservoir measuring 20 meters long, 18 meters wide, and 1.5 meters deep. After 0.8 hours, the water depth reaches 0.6 meters. According to this calculation, how many hours can the empty reservoir be filled? (Answer with proportional knowledge)
自来水厂向一个从里面量长20米，宽18米，深1.5米的空蓄水池里注水，经过0.8小时水深达0.6米，照这样计算，几小时能把空池注满？(用比例知识解答)
<gadget id="calculator">20 * 18 * 1.5 * 0.8</gadget>
<output>432</output>

<gadget id="calculator">20 * 18 * 0.6</gadget>
<output>216</output>

<gadget id="calculator">432 / 216</gadget>
<output>2</output>

<result>2</result>