Following the Neolithic Revolution, a group of people formed a farming community along the Euphrates River, the people no longer needed to hunt or gather food. The discovery of agriculture had the people build dwellings and permanent settlements in order to carry out the whole process of planting seeds, irrigating the fields, oversee the growth of their crops and finally harvest their crops. Also, methods for preserving corn were developed which further increased the attachment of people to one fixed place and drastically decreased their dependence on hunting and gathering food for a living.
It is important for cities to be near a harbor because this increases trade which leads to a stronger financial economy. Hope this helps! Please let me know if I'm wrong. :)
So, take the goal and divide that by the constant. If you get a number around the origin that probably means that you're way off you inconsiderate dipstick (Quoted by Chamy the Cham Cham Chamslam). Now, to get yourself out of the sticky situation all you have to do is subtract your age by the goal, that easy.