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?