A business hall opens at 6:30 in the morning and closes at 6:00 in the afternoon, how many hours in total are the business hours each day?
某营业厅上午6：30开始营业，下午6：00停止营业，每天的营业时间一共多少小时．
<gadget id="calculator">12 - 0.5</gadget>
<output>11.5</output>

<result>11.5</result>