The weight ratio of A and B piles of coal is 12:7. After A pile is shipped out (1/4), A is 6 tons more than B. How many tons does A have?
甲乙两堆煤重量比是12：7，甲堆运出(1/4)后，甲比乙还多6吨，原来甲多少吨？
<gadget id="calculator">12 + 7</gadget>
<output>19</output>

<gadget id="calculator">12 / 19</gadget>
<output>12/19 = around 0.631579</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">(12/19) * (3/4)</gadget>
<output>9/19 = around 0.473684</output>

<gadget id="calculator">7 / 19</gadget>
<output>7/19 = around 0.368421</output>

<gadget id="calculator">(9/19) - (7/19)</gadget>
<output>2/19 = around 0.105263</output>

<gadget id="calculator">6 / (2/19)</gadget>
<output>57</output>

<gadget id="calculator">57 * (12/19)</gadget>
<output>36</output>

<result>36</result>