Mr. Wang goes to work at 7:30 every morning, leaves work at 11:30 noon, goes to work at 1:30 pm, and leaves work at 5:30, how many hours does he work in a day?
王老师每天早上7：30上班，中午11：30下班，下午1：30上班，5：30分下班，他一天工作多少小时．
<result>8</result>