There is a batch of goods in the warehouse, and the weight ratio of the transported goods to the remaining goods is 2:7. If another 20 tons are transported away, then the remaining goods are 2/3 of the original goods in the warehouse. How many tons are the original goods in the warehouse.
仓库有一批货物，运走的与剩下的重量比是2：7，如果又运走20吨，那么剩下的货物是仓库原有货物的(2/3)，仓库原有货物多少吨．
<gadget id="calculator">7 / 9</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(7/9) - (2/3)</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">20 / (1/9)</gadget>
<output>180</output>

<result>180</result>