There are 20 tons of coal in the cafeteria, and the average daily coal consumption in the first 15 days is 0.6 tons. The remaining coal burns 0.55 tons per day, how many days can it be burned?
食堂有煤20吨，前15天平均每天烧煤0.6吨．剩下的煤，每天烧0.55吨，还可以烧多少天？
<gadget id="calculator">15 * 0.6</gadget>
<output>9</output>

<gadget id="calculator">20 - 9</gadget>
<output>11</output>

<gadget id="calculator">11 / 0.55</gadget>
<output>20</output>

<result>20</result>