There are two piles of coal, A and B. Pile A weighs 20 tons, which is 20% heavier than Pile B. How many tons of coal does Pile B have?
甲、乙两堆煤，甲堆重20吨，比乙堆重20%，乙堆煤有多少吨？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">20 / (6/5)</gadget>
<output>50/3 = around 16.666667</output>

<result>50/3 = around 16.666667</result>