The distance between two cities on a map is 18 cm. what is the actual distance between the cities if the map is drawn at a scale of 1: 500,000?

Math it's appreciated. (picture provided)

Afarmer has a large field that is x feet in length. he wants to fence in a rectangular section in the middle of the field , leaving a length of 100 feet of open field behind each end of the fenced rectangle.he also wants the width of the fenced-in space to be 100 feet less than its length. find the expressions to represent the length and width of the fenced section of the field

Solve for x and select the correct answer