The Impossible Figure

Riddle: If half of 5 were 3, what would one-third of 10 be?

Answer: If half of five is three, then half of ten is six, which would make it twelve, and a third of twelve is four.

Source: https://www.riddles.com/6483

If half of 5 were 3, what would one-third of 10 be? — The Impossible Figure by Eric Mason v1.

Riddle: If half of 5 were 3, what would one-third of 10 be? Answer: If half of five is three, then half of ten is six, which would make it twelve, and a third of twelve is four. — by Eric Mason v2.