A small car can transport 2.5 tons of coal each time, and a large car can transport 7.5 tons of coal each time. There are 100 tons of coal in the coal yard, first transported 8 times by large trucks, and the rest by small trucks, at least how many times will it take to transport all the coal?
一辆小车每次可运煤2.5吨，一辆大车每次可运煤7.5吨．煤场上有100吨煤，先用大车运8次，剩下的由小车运，至少还需要多少次才能将煤全部运完？
<gadget id="calculator">7.5 * 8</gadget>
<output>60</output>

<gadget id="calculator">100 - 60</gadget>
<output>40</output>

<gadget id="calculator">40 / 2.5</gadget>
<output>16</output>

<result>16</result>