The way I head this 60 years ago is as follows:
If it takes a man a week to run a fortnight,
how long would it take to swim through a barrel of treacle with clogs on?
So the answer is obviously a lemon.
Explained: Suck it and see.
Meaning: If you waste your time on nonsence riddles you'll end up screwing up your face trying to make sense of them as you would if you suck a lemon.