A barrel of oil weighs 122.5 kilograms. After half of the oil is sold, the remaining oil and the barrel weigh 62.5 kilograms. How much is the net weight of the barrel of oil?
一桶油连桶重122.5千克，卖出油的一半后，剩余的油和桶共重62.5千克，这桶油净重多少千克？
<gadget id="calculator">122.5 - 62.5</gadget>
<output>60</output>

<gadget id="calculator">60 * 2</gadget>
<output>120</output>

<result>120</result>