There were several tons of chemical fertilizers in the warehouse, half of which was taken out for the first time, more than 30 tons, the remaining half was taken out for the second time, 100 tons less, the remaining 25% was taken out for the third time, and the rest was taken out for the fourth time (3/11) , there are still 120 tons left. How many tons of this batch of chemical fertilizers are there?
仓库里原有化肥若干吨，第一次取出全部的一半多30吨，第二次取出余下的一半少100吨、第三次取出余下的25%，第四次取出余下的(3/11)，还剩下120吨，这批化肥原来有多少吨？
<gadget id="calculator">3 / 11</gadget>
<output>3/11 = around 0.272727</output>

<gadget id="calculator">1 - (3/11)</gadget>
<output>8/11 = around 0.727273</output>

<gadget id="calculator">25 / 100</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">120 / (8/11) / (3/4)</gadget>
<output>220</output>

<gadget id="calculator">220 - 100</gadget>
<output>120</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">120 / (1/2)</gadget>
<output>240</output>

<gadget id="calculator">240 + 30</gadget>
<output>270</output>

<gadget id="calculator">270 / (1/2)</gadget>
<output>540</output>

<result>540</result>