Two species coexist in the same ecosystem. Species I has population P(t) in t years, while Species II has population Q(t), both in thousands, where P and Q are modeled by the functions

for all times t ≥ 0 for which the respective populations are nonnegative.

a. What is the initial population of each species?

b. What happens to P(t) as t increases? What happens to Q(t)?

c. Sketch the graphs of P(t) and Q(t).

P(t) = 30 3+ t and Q(t) = 64 4-t