Question

A comet is in an elliptical orbit around the Sun. Its closest approach to the Sun is a distance of 4.8 x10^10 m (inside the orbit of Mercury), at which point its speed is 9.1 x10^4 m/s. Its farthest distance from the Sun is far beyond the orbit of Pluto. What is its speed when it is 6 x10^12 m from the Sun? (This is the approximate distance of Pluto from the Sun.)