In order to save water, a city’s water company stipulates that when each person uses less than 3 tons of water per month, they will be charged 2.6 yuan per ton, and the part that exceeds 3 tons will be charged 3.5 yuan per ton. According to this calculation, a monthly family of 5 people, I used 16.4 tons of water last month, how much should I pay for water?
为了节约用水，某市自来水公司规定：每人每月用水不超过3吨时，按每吨2.6元收费，超过3吨的部分按每吨3.5收费，照这样计算，月月家5口人，上月共用了16.4吨水，应交水费多少元？
<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<gadget id="calculator">16.4 - 15</gadget>
<output>1.4</output>

<gadget id="calculator">1.4 * 3.5</gadget>
<output>4.9</output>

<gadget id="calculator">2.6 * 3 * 5</gadget>
<output>39</output>

<gadget id="calculator">4.9 + 39</gadget>
<output>43.9</output>

<result>43.9</result>