Governor's Cup Drager BG4 Exam Taken from the 2019 Governor's Cup Mine Rescue Contest held in Wise, Virginia Progress Indicator: Question 2 of 20 2.  If a 36,000 cfm airflow passes through a duct with a cross-sectional area of 3 square feet, the air velocity through the duct could be accurately measured using a: Choices: smoke tube. medium-velocity vane type anemometer. high-velocity vane type anemometer with multiplier gauge. pitot tube both c and d.