A population of bacteria begins with 1 bacterium and triples every hour. Which equation can be used to model this situation?

A. y = 3x

B. y = 3x^2

C. y = x^3

D. y = 3^x

Suppose that a population of bacteria triples every hour and starts with 500 bacteria.

Find an expression for the number n of bacteria after t hours.

i know it's something like 500e^kt

but i don't know how to do it. or what k is and i know you're supposed to do natural log or something.