The original area of the reservoir was 1.6 square kilometers, but it was increased to 1.9 square kilometers after treatment. How many hectares has the reservoir area increased?
水库原来面积是1.6平方千米，治理后增加到1.9平方千米，水库面积增加了多少公顷．
<gadget id="calculator">1.9 - 1.6</gadget>
<output>0.3</output>

<gadget id="calculator">0.3 * 100</gadget>
<output>30</output>

<result>30</result>