I need help with these two problems please.

2. A cold beer initially at 35F warms up to 40F in 3 min while sitting in a room of temperature 70F. How warm will the beer be if left out for 20 min? 6. On a mild Saturday morning while people are working inside, the furnace keeps the temperature inside the building at 21C. At noon the furnace is turned off, and the people go home. The temperature outside is a constant 12C for the rest of the afternoon. If the time constant for the building is 3 hr, when will the temperature inside the building reach 16C? If some windows are left open and the time constant drops to 2 hr, when will the temperature inside reach 16C