newton's Law of Gravitation can be used to show that if an
object weighs w pounds on the surface of the
earth, then its weight at distance x from the
center of the earth is
W(x) = wR^2/x^2
(for x ≥ R)
where R = 3,960 miles is the radius of the
earth. At which altitude would an 130-lb person weigh
129.5lbs? (Round your answer to two decimal