A horse is tied to a five meter rope in front of an old saloon. Six meters behind the horse is a bale of hay. Without breaking his rope, the horse is able to eat the hay whenever he chooses.
The rope is not tied to anything else.
Một tá chiếc móc khóa gồm bao nhiêu chiếc chìa khóa?
Chỉ có móc thì không có chìa