Air with a volumetric flow rate of 6 m3/min, enters to a room having 180 m3 volume and leaves the room at the same flow rate. There is 0.03% (by volume) CO2 in the air feed entering the room. At the beginning, room air contains 0.05%CO2 volumetrically. When the amount of CO2 in the room exceeds 0.1%, breathing will be difficult. According to this, find the maximum number of people that can stay in the room for a time period of about 30 minutes by assuming that each person gives off 4.5 x 10-6 m3 CO2/s through breathing.