A car travels a distance of 450 km in a straight line for 4.50 hours from Hither to Yon. The car then returns to Hither from Yon in a straight line at 90.0 km/h. Answer the following questions based on this information:

a) What is the car's average speed, in km/h, from Hither to Yon for the first part of the trip?

b) How long, in hours, did it take for the car to return to Hither from Yon?

c) What is the average velocity of the car for the entire (whole) journey, from Hither to Yon, and back to Hither?