(Modeling) Distance from the Origin of the Nile River The Nile River in Africa is about 40...

(Modeling) Distance from the Origin of the Nile River The Nile River in Africa is about 4000 mi long. The Nile begins as an outlet of Lake Victoria at an altitude of 7000 ft above sea level and empties into the Mediterranean Sea at sea level (0 ft). The distance from its origin in thousands of miles is related to its height above sea level in thousands of feet (x) by the rational expression

For example, when the river is at an altitude of 600 ft,x = .6 (thousand), and the distance from the origin is

which represents 3000 mi. (Source: The World Almanac and Book of Facts.)

Find the distance from the origin of the Nile when the river is 1200 ft high.