A certain team transports a pile of coal. On the first day (2/7) the pile of coal is transported 20 tons less than on the second day. At this time, the weight ratio of the coal removed to the rest is 9:5. The pile of coal How many tons?
某车队运一堆煤，第一天运走这堆煤的(2/7)，比第二天少运20吨，这时运走的煤和余下的重量比是9：5，这堆煤有多少吨？
<gadget id="calculator">9 + 5</gadget>
<output>14</output>

<gadget id="calculator">9 / 14</gadget>
<output>9/14 = around 0.642857</output>

<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">(9/14) - (2/7) - (2/7)</gadget>
<output>1/14 = around 0.071429</output>

<gadget id="calculator">20 / (1/14)</gadget>
<output>280</output>

<result>280</result>