A new batch of rice in a grain store sells 1/5 of the total on the first day, and 120 kg on the second day. At this time, the ratio of the rest to the sold is 2:1. How much is this batch of rice? kilogram?
某粮店新进一批大米，第一天卖出总数的(1/5)，第二天卖出120千克，这时剩下的与卖出的比是2：1，这批大米有多少千克？
<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/3) - (1/5)</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">120 / (2/15)</gadget>
<output>900</output>

<result>900</result>