Yes, 100 miles is the correct answer, but how did you get it?
Bees must be able to fly in a straight line, otherwise why would we make a beeline for anything?! Oh, and that's the name of the rail track: the bee-line.
As for speed, well, yes, they only reach a maximum of 20mph, so we have a make-bee-lieve bee, or a beebot (like a drone) straight from sci-fi, or a mathematical text book, where anything goes.