Final answer:
The lorry travels 6 mph faster than the expected speed. It was meant to travel 200 miles at 40 mph but ended up traveling a 15% longer route of 230 miles in the same time frame, resulting in an actual speed of 46 mph.
Step-by-step explanation:
The original shortest route from London to Manchester is 200 miles, and the lorry was expected to take 5 hours to travel this distance. Therefore, the expected average speed is 200 miles / 5 hours = 40 mph.
However, the lorry travels a different route which is 15% longer. An increase of 15% on 200 miles is 30 miles (0.15 x 200), making the new distance 230 miles (200 + 30). Yet, the lorry still arrives in 5 hours. So, the actual average speed is 230 miles / 5 hours = 46 mph.
To find how many more mph the lorry travels compared to the expected speed, we subtract the original average speed from the new average speed: 46 mph - 40 mph = 6 mph. Therefore, the lorry travels 6 mph faster than the expected speed.