The water company stipulates: "When the water consumption per person per month does not exceed 2 tons, the fee is 0.8 yuan per ton, and the part that exceeds 2 tons is charged at 5 yuan per ton." According to this calculation, Li Ming's family of 3 people used 8.5 tons of water last month. , How much should I pay for water?
自来水公司规定："每人每月用水不超过2吨时，按每吨0.8元收费，超过2吨的部分按每吨5元收费．"照这样计算，李明家3口人，上月用水8.5吨，应交水费多少钱？
<gadget id="calculator">2 * 3</gadget>
<output>6</output>

<gadget id="calculator">0.8 * 6</gadget>
<output>4.8</output>

<gadget id="calculator">8.5 - 6</gadget>
<output>2.5</output>

<gadget id="calculator">5 * 2.5</gadget>
<output>12.5</output>

<gadget id="calculator">4.8 + 12.5</gadget>
<output>17.3</output>

<result>17.3</result>