Why did the incans build such a large road network in their empire?

The Incas built such a  large road network stretching for 1000's of kilometers north and south of Cuzco, their capital, in what is now Peru, in order to keep the lines of communication open with their far flung empire, ie to convey messages to their local rulers, and probably for military purposes to have routes for their armies to follow in times of war. The roads were built by the ordinary people ie the men of  a certain age would be subject to the mit'a or compulsory public service to build roads, temples and work in the mines.

12 days because 1/4 is 25% of 100 if 100 is equal to 1 pound then multiply 3 by 4 which equals 12

Economic success prussia had a very strong economy, partly due to the success of the zollverein. stronger prussian army king wilhelm wanted to build a bigger, stronger army but was blocked by the prussian landtag (parliament).-credits to google for putting answer -credits to slideshare for making answer-credits to me for putting answer on brain.ly