The school cleaners have to clean up 48 boxes of garbage, and 12 boxes have been cleaned up. If 9 boxes are cleaned every hour, can it be cleaned in 5 hours?
学校保洁员要清理48箱垃圾，已经清理了12箱．如果每小时清理9箱，5小时能清理完么？
<result>5</result>