Xiaogang’s family shared 20 tons of water last month, and charged 1.5 yuan per ton of water. There are 4 people in Xiaogang’s family. How much was the average water bill per person last month?
小刚家上个月共用水20吨，每吨水收费1.5元，小刚家共有4口人，上个月平均每人交水费多是元？
<gadget id="calculator">1.5 / 4</gadget>
<output>0.375</output>

<gadget id="calculator">20 * 0.375</gadget>
<output>7.5</output>

<result>7.5</result>