tractor pulls soil to the construction site. Working for 4 hours in the morning, a total of 73.2 tons of soil was pulled, and 3 hours of work in the afternoon, an average of 20.4 tons of soil was pulled per hour. How many tons of soil was pulled by this tractor per hour on average?
一台拖拉机往工地拉土．上午工作4小时，共拉土73.2吨，下午工作3小时，平均每小时拉土20.4吨，这台拖拉机平均每小时拉土多少吨？
<gadget id="calculator">20.4 * 3</gadget>
<output>61.2</output>

<gadget id="calculator">61.2 + 73.2</gadget>
<output>134.4</output>

<gadget id="calculator">4 + 3</gadget>
<output>7</output>

<gadget id="calculator">134.4 / 7</gadget>
<output>19.2</output>

<result>19.2</result>