In order to encourage residents to save water, a community stipulates that the monthly water fee of 15 tons (including 15 tons) is charged at 1.8 yuan per ton, and the excess of 15 tons is charged at 4 yuan per ton. The water fee is 43 yuan. How many tons of water did Xiaoxiao’s family share last month?
为了鼓励居民节约用水，某小区规定，每月用水15吨(含15吨)以内的每吨按1.8元收水费，超出15吨的部分每吨按4元收，笑笑家上月共交水费43元，笑笑家上月共用水多少吨？
<gadget id="calculator">4 * 15</gadget>
<output>60</output>

<gadget id="calculator">15 * 1.8</gadget>
<output>27</output>

<gadget id="calculator">43 - 27</gadget>
<output>16</output>

<gadget id="calculator">60 + 16</gadget>
<output>76</output>

<gadget id="calculator">76 / 4</gadget>
<output>19</output>

<result>19</result>