After installing a water-saving gate in a residential building, each household saves 2.5 tons of water per month on average. If the 54 residents in the building are like this, how many tons of water can be saved in a quarter?
一栋居民楼安装了节水闸门以后，平均每户每月节约用水2.5吨，照这样全楼54户居民，一季度可以节约用水多少吨？
<gadget id="calculator">2.5 * 54 * 3</gadget>
<output>405</output>

<result>405</result>