For a barrel of oil, 20% of the oil is poured out for the first time, 19 kg is poured out for the second time, and the sum of the previous two times is poured out for the third time. At this time, 12.5% of the oil in the barrel remains. How many kilograms?
一桶油，第一次倒出20%，第二次倒出19千克，第三次倒出的是前两次的总和，此时还剩下这桶油的12.5%，这桶油原有多少千克？
<gadget id="calculator">19 + 19</gadget>
<output>38</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">12.5 / 100</gadget>
<output>0.125</output>

<gadget id="calculator">1 - (1/5) - (1/5) - 0.125</gadget>
<output>0.475</output>

<gadget id="calculator">38 / 0.475</gadget>
<output>80</output>

<result>80</result>