There are 72 tons of ore, and 18 tons are transported by 5 vehicles at a time. According to this calculation, how many vehicles are needed to transport the remaining ore at one time?
有矿石72吨，先用5辆汽车一次运走18吨，照这样计算，剩下的矿石一次运完，需要这样的汽车多少辆？
<gadget id="calculator">72 - 18</gadget>
<output>54</output>

<gadget id="calculator">18 / 5</gadget>
<output>18/5 = around 3.6</output>

<gadget id="calculator">54 / (18/5)</gadget>
<output>15</output>

<result>15</result>