For a barrel of oil, 37.5% is poured out for the first time, and the remaining 40% is poured out for the second time. At this time, there are still 30 kilograms left. How many kilograms is this barrel of oil originally?
一桶油，第一次倒出37.5%，第二次倒出剩下的40%，这时还剩下30千克，这桶油原有多少千克？
<gadget id="calculator">37.5 / 100</gadget>
<output>0.375</output>

<gadget id="calculator">1 - 0.375</gadget>
<output>0.625</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">0.625 * (2/5)</gadget>
<output>0.25</output>

<gadget id="calculator">1 - 0.375 - 0.25</gadget>
<output>0.375</output>

<gadget id="calculator">30 / 0.375</gadget>
<output>80</output>

<result>80</result>