Starting with Newton's law of gravitation, determine the height h one person has to go from the surface of Earth in order for the person's weight to be reduced to 1/5 of their weight at the surface of the Earth. The only information you are given is that the radius of the earth is 6400 km.
GM_e/r^2, r = R_e + h
The Attempt at a Solution
i know that 4 times R_e at the center(of earth) is equal to 3 times R_e at the surface. im not sure how to find the height using Newton's Law.