For a barrel of oil, 30% of it is poured out for the first time, and 15 kilograms less than the first poured out for the second time, leaving 65 kilograms. How many kilograms of oil is in this barrel?
一桶油，第一次倒出它的30%，第二次比第一次少倒出15千克，还剩65千克，这桶油有多少千克？
<gadget id="calculator">65 - 15</gadget>
<output>50</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (3/10) - (3/10)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">50 / (2/5)</gadget>
<output>125</output>

<result>125</result>