The growth of a population of water fungus is modeled by the function y = f (x) = 2.68(3.84)x where x represents the number of hours elapsed and y represents the number of fungi spores.
a. How many spores are there initially?
b. How many spores are there after 10 h?
c. Find an inverse function that uses y as the dependent variable and x as the independent variable.
d. Use your answer to 15c to find how long it will take until the number of spores exceeds 1 billion.