A barrel of oil, pour out (2/5) for the first time, pour out 20 kg for the second time, and there are 28 kg left in the barrel. How many kilograms is this barrel of oil originally?
一桶油，第一次倒出(2/5)，第二次倒出20千克，桶里还剩下28千克．这桶油原来有多少千克？
<gadget id="calculator">20 + 28</gadget>
<output>48</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">48 / (3/5)</gadget>
<output>80</output>

<result>80</result>