The area of a rectangular campus is 6 hectares. If the width remains the same and the length is tripled, what is the area of the campus after expansion?
一个长方形校园的面积是6公顷，若宽不变，长扩大到原来的3倍，扩建后校园的面积是多少公顷．
<gadget id="calculator">6 * 3</gadget>
<output>18</output>

<result>18</result>