Question

The appromiate mass of a comet X has been memasured. When comet X orbits the Sun 5000 years later it only has half it's previous mass.
Approximately how many orbits of the Sun has the comet completed and what is the period of the comets orbit?

Answer 1

More information is needed to answer that. The mass loss per orbit depends upon how close it comes to the sun, what it is made of, and the period of the orbit.

Answer 2

This dialogue on that subject may be helpful:
http://www.bautforum.com/archive/index.php/t-110161.html