I would say about 3,000 to 3,500 miles. :) I hope I helped, Good luck!
The Silk Road trade allowed for diffusion of technologies to go throughout Eurasia. For instance, silk-making technology from China was able to diffuse and reach areas in Europe. Another example would be the religion of Buddhism. Buddhism originated in India and made its way to China along the Roads, and changed a bit along the way.
Tariff is the correct answer
