For a barrel of oil, pour out (2/5) for the first time, and pour out 2 kilograms for the second time. At this time, the remaining oil in the barrel still accounts for (2/5) of the whole barrel. How many kilograms does this barrel of oil weigh?
一桶油，第一次倒出(2/5)，第二次倒出2千克，这时桶里剩下的油还占整桶的(2/5)，这桶油重多少千克？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5) - (2/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">2 / (1/5)</gadget>
<output>10</output>

<result>10</result>