Here is my problem:

"A bacteria culture grows with the constant relative growth rate. After 2 hours there are 600 bacteria and after 800 hours the count is 75,000.

Find the initial population."

I know I need to use P(t)=P(0)(e^kt) but can't figure out how to solve for P(0). I'm sure it is probably obvious, but I am stumped. Any help is appreciated.