A pile of coal burns 12.4 tons per day and can be burned for 25 days. If it burns 10 tons per day, how many days can it be burned?
一堆煤，每天烧12.4吨，可以烧25天，如果每天烧10吨，可以烧多少天？
<gadget id="calculator">25 / 10</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">12.4 * (5/2)</gadget>
<output>31</output>

<result>31</result>