I am trying to write a formula that will figure out how many sections will go
into a number. The sections have to be between 10 and 20 feet each. For
example: If I have a 40 foot section, 2 20 foot sections will go evenly. If
I have a 50 foot section, 2 20 foot sections and 1 10 foot section.
Moreover, for a 25 foot section, it has to be 2 12.5 foot sections or 1 10
foot section and one 15 foot section, not 1 20 foot section and 1 5 foot
section, because all sections have to be between 10 and 20 feet.
So, each section has to be between 10 and 20 feet and I am trying to get as
few number of sections as possible.

Anyone have any idea how to accomplish something crazy like this with a
formula or even in multiple steps?