Selling rainbowfish

In section 1.4 you encountered the problem of predicting the number of rainbowfish when you are breeding them.

A mathematical model was formulated in the form of a differential equation and a solution was found. However, this solution is unrealistic: the number of rainbowfish grows very large very quickly.

In this section we will add one sentence to the problem, in the hope that this will limit the growth. We have chosen the following addition:

The aquarium owner expects to sell 20 rainbowfish every day.

In the following pages of this section, you will incorporate this into the model, investigate the long-term solutions and validate them.