The original 42 tons of coal in the machine factory burned for 20 days, an average of 1.5 tons of coal per day, and the remaining coal burned 1.2 tons per day. How many more days can it burn?
机器厂原有42吨煤，烧了20天，平均每天烧煤1.5吨，剩下的煤每天烧1.2吨，还可以烧多少天？
<gadget id="calculator">1.5 * 20</gadget>
<output>30</output>

<gadget id="calculator">42 - 30</gadget>
<output>12</output>

<gadget id="calculator">12 / 1.2</gadget>
<output>10</output>

<result>10</result>