1. The problem statement, all variables and given/known data Flies, frogs, and crocodiles coexist in an environment. To survive, frogs need to eat flies and crocodiles need to eat frogs. In the absence of frogs, the fly population will grow exponentially and the crocodile population will decay exponentially. In the absence of crocodiles and flies, the grog population will decay exponentially. If P(t) , Q(t), and R(t) represent the populations of these three species at time t, write a system of differential equations as a model for their evolution. If the constants in your equation are all positive, explain why you have used plus or minus signs. 2. Relevant equations Not really sure how to do this or where to start at. 3. The attempt at a solution I said Dp/dt is for my crocs so p is that variable to represent crocidiles. I said dq/dt is for frogs so q is the variable for frogs and dr/dt is for flies so r is for flies. I'm having trouble to get going here.