A piece of coal was originally planned to burn 6 tons per day, and it can be burned for 72 days. After the boiler is improved, it only burns 4.8 tons per day. How many days can this pile of coal be burned?
一块煤原计划每天烧6吨，可以烧72天，改进锅炉后，每天只烧4.8吨，这堆煤可以烧多少天？
<gadget id="calculator">72 / 4.8</gadget>
<output>15</output>

<gadget id="calculator">6 * 15</gadget>
<output>90</output>

<result>90</result>