A pile of coal, originally planned to burn 3 tons per day, can be burned for 72 days. After the boiler is remodeled, it only burns 2.4 tons per day. How many days can this pile of coal be burned now?
一堆煤，原计划每天烧3吨，可以烧72天，改造锅炉后，每天只烧2.4吨，这堆煤现在可以烧多少天？
<gadget id="calculator">72 / 2.4</gadget>
<output>30</output>

<gadget id="calculator">3 * 30</gadget>
<output>90</output>

<result>90</result>