A barrel of oil weighs 12.65 kilograms. After half of it is used up, the barrel still weighs 6.85 kilograms. How many kilograms does the barrel weigh?
一桶油连桶共重12.65千克，用去一半后，连桶还重6.85千克，桶重多少千克？
<result>11.05</result>