For a pile of coal, 1/4 of the total amount was burned on the first day, and 20% of the total amount was burned on the second day, leaving 5.5 tons. How many tons is this pile of coal?
一堆煤，第一天烧了总数的(1/4)，第二天烧了总数的20%，还剩5.5吨．这堆煤共有多少吨？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/4) - (1/5)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">5.5 / (11/20)</gadget>
<output>10</output>

<result>10</result>