The original batch of coal in the canteen burns 0.2 tons per day and can be burned for 30 days. If you burn 0.1 tons more every day, how many days can you burn?
食堂原来一批煤，每天烧0.2吨，可以烧30天．如果每天多烧0.1吨，可以烧多少天？
<gadget id="calculator">0.2 * 30</gadget>
<output>6</output>

<gadget id="calculator">0.2 + 0.1</gadget>
<output>0.3</output>

<gadget id="calculator">6 / 0.3</gadget>
<output>20</output>

<result>20</result>