I have no clue. But I am sure that there is a palaeontologist out there who could help you out...given that we think that Sue was about 25 years old at time of death, we have a pretty good idea as to max life spans of a TRex...the question of how often it bred and what amount of square miles could support each individual are questions that can never be answered, but I am sure that we can make some assumptions and work up a numerical range for you.....however math is not my strong suit...what are you getting at, anyhow?
Okay, just for the sake or discussion, let's say the T. Rex's average life span was 25 years and a heterosexual couple of T. Rex's spawned one t. Rex in their lifespans. So at minimum, there would be one new T. Rex every 25 years. At that rate, how many T. Rex's would have been born in 5 million years?