The Shengli Steel Plant has 78 tons of coal and has been burning for 16 days, averaging 2.4 tons per day. If the remaining coal is burning 2.2 tons per day, how many more days can it burn? (solution by equation)
胜利炼钢厂有78吨煤，已经烧了16天，平均每天烧2.4吨，剩下的煤如果每天烧2.2吨，还可以烧多少天？(用方程解)
<gadget id="calculator">2.4 * 16</gadget>
<output>38.4</output>

<gadget id="calculator">78 - 38.4</gadget>
<output>39.6</output>

<gadget id="calculator">39.6 / 2.2</gadget>
<output>18</output>

<result>18</result>