Answer:
average speed of the truck will be 60 km/h
Step-by-step explanation:
Truck started his Journey from diner at 1:00 PM
It reached to the Jersey City at 7:00 PM
so here we have total time interval of journey for the truck motion is given as

total distance = 360 km
so here we know that average speed is defined as



so average speed of the truck will be 60 km/h