Xiaohong’s family used 9 tons of water last month and paid a water fee of 45 yuan; Xiaoming’s family used 16 tons of water last month, how much water fee do they need to pay? (Solve with ratio)
小红家上个月用了9吨水，交了45元水费；小明家上个月用了16吨水，需要交多少钱水费？(用比例解)
<gadget id="calculator">45 / 9</gadget>
<output>5</output>

<gadget id="calculator">5 * 16</gadget>
<output>80</output>

<result>80</result>