The equation y= 39 4x describes the number of miles y that an airplane travels in x minutes. What is the constant speed of the airplane in miles per minute? How many miles does the airplane travel in 4 hours?

Speed: distance traveled in a given time

y=distance ( given in miles).
x = time (given in minutes)

Speed = y/x

y = 39.4x

By rearranging this y/x =39.4 ( is the constant speed). don’t forget this is mile/minutes

There are 4 x 60 minutes in 4 hours

Hence, you are asked the distance (y) in 240 min

y = 39.4x
y = 39.4 miles/minutes x (240) minutes

y = 9456 miles