A proportionality puzzle: If half of $5$ is $3$, then what's one-third of $10$? My professor gave us this problem.

In a foreign country, half of 5 is 3. Based on that same proportion, what's one-third of 10?

I removed my try because it's wrong.

They say $\frac{5}{2}$ is $3$, when really it's $2.5$.
They say $\frac{10}{3}$ is $x$, when really it's $3.\overline{3}$.
Simple relational proportion:
$$ \frac{3}{2.5} = \frac{x}{3.\overline{3}} \implies x = 4 $$
