On a mild Saturday morning while people are working inside, the furnace keeps the temperature inside the building at 22 C. At noon the furnace is turned off, and the people go home. The temperature outside is a constant 15C for the rest of the afternoon. If the time constant for the building is 3 hr, when will the temperature inside the building reach 18 C? If some windows are left open and the time constant drops to 2 hr, when will the temperature inside reach 18 C? If the time constant for the building is 3 hr, the temperature inside the building will reach 18 C about |hr after noon. (Round to the nearest tenth as needed.) If the time constant for the building drops to 2 hr, the temperature inside the building will reach 18C about |hr after noon. (Round to the nearest tenth as needed.)