The hotel has 100 standard rooms, and the price is 400 yuan per day, but the occupancy rate is only 50%. If the house price is reduced by 20 yuan, 5 rooms can be added. Find the right room rate so that the hotel receives the highest room rate.
酒店有100个标准间，房价为400元/天，但入住率只有50%．若每降低20元的房价，则能增加5间入住．求合适的房价，使酒店收到的房费最高．
<result>300</result>