There are two warehouses, A and B. It is known that the weight of grain stored in warehouse A is three times that of warehouse B. If warehouse A transports 30 tons and warehouse B transports 100 tons, the weight of grain stored in warehouse A is twice that of warehouse B. How many tons of grain are stored in Warehouse B now?
甲、乙两个仓库，己知甲仓库存粮的重量是乙仓库的3倍，如果甲仓库运进30吨，乙仓库运进100吨，这时甲仓库存粮的重量是乙仓库的2倍，现在乙仓库存粮多少吨？
<gadget id="calculator">100 * 2</gadget>
<output>200</output>

<gadget id="calculator">200 - 30</gadget>
<output>170</output>

<gadget id="calculator">3 - 2</gadget>
<output>1</output>

<gadget id="calculator">170 / 1</gadget>
<output>170</output>

<gadget id="calculator">170 + 100</gadget>
<output>270</output>

<result>270</result>