A canteen transported back 325 kg of coal and planned to burn it in 6.5 days, but actually saved 17.5 kg per day. How many days did the coal actually burn?
一个食堂运回325千克煤，计划6.5天烧完，实际每天节省了17.5千克．这些煤实际烧了多少天？
<gadget id="calculator">325 / 6.5</gadget>
<output>50</output>

<gadget id="calculator">50 - 17.5</gadget>
<output>32.5</output>

<gadget id="calculator">325 / 32.5</gadget>
<output>10</output>

<result>10</result>