I have heard a version of the ‘hen and a half’ question for many years that goes:
If a hen and a half
can lay an egg and a half
in a day and a half
How many can she lay in a week?
Given your algebra we know the answer to be 4 2/3 (7 * 2/3) but of course the answer is 4 to allow for the wear and tear on the chicken.
Not much of a joke I admit but I enjoyed seeing the variation treated so analytically on the web site.