Liu Wei’s water meter read 125 tons in July and 146 tons in August, and she paid 3.7 yuan per ton of water. How much does Liu Wei's family pay for water in August?
刘薇家七月份水表读数为125吨，八月份水表读数为146吨，每吨水付费3.7元．刘薇家八月份付水费多少元．
<gadget id="calculator">146 - 125</gadget>
<output>21</output>

<gadget id="calculator">3.7 * 21</gadget>
<output>77.7</output>

<result>77.7</result>