A comet goes around the Sun in an elliptical orbit. At its farthest point, 405 million miles from the Sun, it is traveling with a speed of 15455 mi/h. How fast is it traveling at its closest approach to the Sun, at a distance of 166 million miles?

I'm not sure what level you're at so I'm not sure what assumptions I can make.

How do you think you should go about doing it?