A certain city stipulates that the monthly water consumption standard for a family of three is 6 tons, and the water fee per ton is 3.7 yuan. Exceeding the specified water consumption is 7 yuan per ton. Li Ming's family paid 39 yuan for water in June. How many tons is the excess water consumption this month?
某市规定三口之家每月用水标准是6吨，每吨水费是3.7元．超过规定用水量每吨7元．李明一家六月份交水费39元．这个月超过规定用水量是多少吨？
<gadget id="calculator">3.7 * 6</gadget>
<output>22.2</output>

<gadget id="calculator">39 - 22.2</gadget>
<output>16.8</output>

<gadget id="calculator">16.8 / 7</gadget>
<output>2.4</output>

<result>2.4</result>