There is a batch of goods in the warehouse. After being shipped out (3/5), 20 tons are brought in again. At this time, the goods in the warehouse are exactly the original (2/3). How many tons of goods were originally in the warehouse?
仓库里有一批货物，运出(3/5)后，又运进20吨，这时仓库里的货物正好是原来的(2/3)．仓库里原来有货物多少吨？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/3) - (2/5)</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">20 / (4/15)</gadget>
<output>75</output>

<result>75</result>