How long did tyrannosaurus rex live for?

It depends on the age of the Tyrannosaurus in question.

The largest known from a fairly complete skeleton is Sue, which reached a length of 12.8 metres. However, a skull of a T. rex, MOR 008, is significantly larger, and using the skull-body length ratio system we can deduce a slightly longer creature.

And it's A Tyrannosaurus rex, not an. I mean seriously man, come on!