The equation for the distance travelled by the plane is,

a)
Solve the equation for time t.

So equation for t is t = d/r.
b)
The rate for the plane flies is r = 500 miles per hour.
The distance travelled by the plane is d = 4500 miles.
Substitute the values in the equation to determine the value of t.

So plane takes 9 hours to travel 4500 miles.
Answer: 9 hours