I solved this problem in Blender [1] in the past using python's `random.triangular()` [2], and the name suggests this problem is the best example of when you would need `triangular()` and how its distribution works.

[1] https://blender.stackexchange.com/a/221597/60486 [2] https://docs.python.org/3/library/random.html#random.triangu...