This exercise uses the population growth model. Some bullfrogs were introduced into a small pond. The graph shows the bullfrog population for the next few years. Assume that the population grows exponentially. nA 700- 600 Frog population 400- 500- 300- (2, 225) 200- 100- 0 2 3 -4 4 5 6 t (a) What was the initial bullfrog population? bullfrogs (b) Find a function that models the bullfrog population t years since the bullfrogs were put into the pond. (Round your r value to four decimal places.) n(t) = (c) What is the projected bullfrog population after 15 years? bullfrogs (d) Estimate how long it takes the population to reach 124,000. (Round your answer to the nearest whole number.)