There are two piles of coal, the first pile is transported away (1/4), the second pile is 60% left after a part of the coal is removed, the weight ratio of the remaining coal between the first pile and the second pile is 3:4, and the second pile The original coal is 20 tons, how many tons of the first pile of original coal?
有两堆煤，第一堆运走(1/4)，第二堆煤运走一部分后还剩下60%，余下的煤第一堆与第二堆重量比是3：4，第二堆原有煤20吨，第一堆原有煤多少吨？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(3/4) / (3/4)</gadget>
<output>1</output>

<gadget id="calculator">20 * (3/5) * 1</gadget>
<output>12</output>

<result>12</result>