A barrel of oil weighs 120 kg. After half use, it still weighs 65 kg. How many kg of oil is there in this barrel? How many kg of empty barrel?

A barrel of oil weighs 120 kg. After half use, it still weighs 65 kg. How many kg of oil is there in this barrel? How many kg of empty barrel?

120-65 = 55 kg
65-55 = 10kg
120-10 = 110kg
A: the original weight is 110 kg and the barrel weight is 10 kg