or something like that, I'm never too sure.
Hang on. I've been leading you down a path that's more complicated than it needs to be. The reason is that
I can define and I'm left with
Thus, mathematically, we don't gain any flexibility in constructing our function by having both n and r available.
Bottom line: change our initial function to this:
You now have only one equation to solve:
Did you follow all that?
Excellent. So the first colony's population, which we'll now call satisfies the equation
In order to solve the problem in the OP, you're going to need to repeat this process of finding the equation for the second colony's population. What do you get for that?