A bacterial culture starts with 264 bacteria and doubles in size every 4.5 hours. Write a model for the number of bacteria after LaTeX:  \displaystyle t hours.

Since the population dobules every 4.5 hours the function must contain the points LaTeX:  \displaystyle (0,264), (1, 528) , and LaTeX:  \displaystyle (2,1056) . This gives a factor of LaTeX:  \displaystyle 2^\frac{2 t}{9} . The model is LaTeX:  \displaystyle P=264\cdot 2^\frac{2 t}{9} .