The agricultural machinery factory has 39 tons of coal, which has been burned for 16 days, averaging 1.2 tons of coal per day. If the remaining coal is burned 1.1 tons per day, how many days can it be burned?
农业机械厂有39吨煤，已经烧了16天，平均每天烧煤1.2吨．剩下的煤如果每天烧1.1吨，还可以烧多少天？
<gadget id="calculator">1.2 * 16</gadget>
<output>19.2</output>

<gadget id="calculator">39 - 19.2</gadget>
<output>19.8</output>

<gadget id="calculator">19.8 / 1.1</gadget>
<output>18</output>

<result>18</result>