The fertilizer factory transported a batch of fertilizers to the countryside. It was originally planned to use 4.5-ton trucks, but 10 trucks were needed. If they were to be transported by 3-ton trucks, how many trucks would be needed? (Solution by proportional method)
化肥厂把一批化肥运往农村，原计划用载重量4.5吨的汽车运，需要10辆；如果改用载重量是3吨的汽车运，需要多少辆汽车？(用比例方法解)
<gadget id="calculator">4.5 * 10</gadget>
<output>45</output>

<gadget id="calculator">45 / 3</gadget>
<output>15</output>

<result>15</result>