Answer:
-16¹/₂ feet per second
Explanation:
average change in altitude in feet per second = change in altitude in feet/change in time in seconds
= -41¹/₄ ft ÷ 2¹/₂ s
= -165/4 ft ÷ 5/2 s
= -165/4 × 2/5 ft/s
= -33/2 feet per second
= -16¹/₂ feet per second