A pile of coal, originally planned to burn 2.5 tons per day, can be burned for 48 days. If 0.1 tons are saved every day, how many days can it be burned?
一堆煤，原计划每天烧2.5吨，可以烧48天，如果每天节约0.1吨，这样可以烧多少天？
<gadget id="calculator">2.5 * 48</gadget>
<output>120</output>

<gadget id="calculator">2.5 - 0.1</gadget>
<output>2.4</output>

<gadget id="calculator">120 / 2.4</gadget>
<output>50</output>

<result>50</result>