An Air-Conditioning System Is Designed to Fill a Room of 10

Multiple Choice

An air-conditioning system is designed to fill a room of 10 m $\times$ 8 m $\times$ 6 m with fresh air every 20 minutes.If the circular air duct has a diameter of 13 cm,calculate the speed of airflow in the duct.

A) None of the answers below
B) 450 m/s
C) 2.4 m/s
D) 7.5 m/s
E) 1.0 m/s