Early Monday morning, the temperature in the lecture hall has fallen to 40degreesF, the same as the temperature outside. At 7:00 font size decreased by 2 Upper A . font size decreased by 2 Upper M ., the janitor turns on the furnace with the thermostat set at 75degreesF. The time constant for the building is StartFraction 1 Over Upper K EndFraction equals3 hr and that for the building along with its heating system is StartFraction 1 Over Upper K 1 EndFraction equalsone half hr. Assuming that the outside temperature remains constant, what will be the temperature inside the lecture hall at 7 : 45 font size decreased by 2 Upper A . font size decreased by 2 Upper M .? When will the temperature inside the hall reach 73degreesF? At 7 : 45 font size decreased by 2 Upper A . font size decreased by 2 Upper M ., the temperature inside the lecture hall will be about nothingdegreesF.