There are two cotton fields with an average yield of 4500 kg of cotton per hectare. The first cotton field is 5 hectares, and the average cotton yield per hectare is 5,300 kilograms; the second cotton field averages 4,000 kilograms of cotton per hectare. How many hectares does the second cotton field have?
有两块棉田，平均每公顷产棉花4500千克．第一块棉田5公顷，平均每公顷产棉花5300千克；第二块棉田平均每公顷产棉花4000千克．第二块棉田有多少公顷？
<gadget id="calculator">5_300 * 5</gadget>
<output>26_500</output>

<gadget id="calculator">4_500 * 5</gadget>
<output>22_500</output>

<gadget id="calculator">26_500 - 22_500</gadget>
<output>4_000</output>

<gadget id="calculator">4_500 - 4_000</gadget>
<output>500</output>

<gadget id="calculator">4_000 / 500</gadget>
<output>8</output>

<result>8</result>