In an air conditioning system, cold air mixes with hot outdoor air before being routed to a room. cold air enters the mixer at 275 k at a rate of 7 kg/s and hot air enters the mixer at 315 k at a rate of 2 kg/s. the entire system is operated at 105 kpa. the air temperature leaving the mixer is 300 k.

a. find the rate of heat transfer to the mixer from the environment in kw.
b. if the maximum air speed in the ducts is 2 m/s, what should the cross-sectional area be for each of the three ducts (hot input, cold input, and exit)?