In order to encourage residents to save water, the water company stipulates that each household will be charged 1.2 yuan per ton for water consumption within 12 tons (including 12 tons) per month, and 5 yuan per ton for more than 12 tons. Wenwen's family paid a total of 24.4 yuan for water last month. How many tons did Wenwen's water last month?
为鼓励居民节约用水，自来水公司规定：每户每月用水12吨以内(含12吨)按每吨1.2元收费，超过12吨的，其超出吨数按每吨5元收费．文文家上月共交水费24.4元，文文家上月用水多少吨？
<gadget id="calculator">1.2 * 12</gadget>
<output>14.4</output>

<gadget id="calculator">24.4 - 14.4</gadget>
<output>10</output>

<gadget id="calculator">10 / 5</gadget>
<output>2</output>

<gadget id="calculator">12 + 2</gadget>
<output>14</output>

<result>14</result>