Xiaoming’s family used 12 tons of water last month, and the water bill was 30 yuan. Xiaohong’s family used 15 tons of water. How much was Xiaohong’s water bill last month? (Solve with ratio)
小明家上个月用了12吨水，水费是30元，小红家用了15吨水，小红家上个月的水费是多少钱？(用比例解)
<gadget id="calculator">30 / 12</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">(5/2) * 15</gadget>
<output>75/2 = around 37.5</output>

<result>75/2 = around 37.5</result>