A barrel of oil weighs 40 kilograms. After half of the oil is poured out, the barrel and oil weigh 22 kilograms. How many kilograms of oil are there?
一桶油连桶重40千克，倒出一半油后，桶和油共重22千克，油原来有多少千克？
<gadget id="calculator">40 - 22</gadget>
<output>18</output>

<gadget id="calculator">18 * 2</gadget>
<output>36</output>

<result>36</result>