A delivery truck drove 203 miles in 3.5 hours. After unloading and loading new cargo, it traveled on another 243 miles for 4.5 hours.

What was the average speed of the truck over its entire route?

Round to the nearest hundredth, if necessary.

55.75 mi/h
56.00 mi/h
58.00 mi/h
63.70 mi/h