By definition, the speed is given by the quotient between the distance traveled and the time it takes to travel that distance. We have then that the expression for speed is as follows
v = d / t
where
d: distance
t: time
Substituting
v = (90feet) / (5s) = 18feets / s
answer
the average rate of the airplane model, in feet per second was 18feets / s
The answer is 6n^3+n^2+6n-4 I hope I helped you!
