Careful- you can't multiply 800 by e before you take care of your exponent.
Your best bet at this point:
A culture of bacteria obeys the law of uninhibited growth. N(t) = N0(e)^kt
If 500 bacteria are initially present and there are 80 after 1 hour, how many will be present after 5 hours? How long is it until there are 20,000 bacteria?
So, 800 = 500e^k and 800 = 1359.14^k
I cant get past this, how do I get the rate, divide each side by 1359.14?? Once I have the rate I can get the rest, correct?