Answer
Converse Error (The argument is invalid)
Work Step by Step
Let $p$ be the statement that Jules solved this problem correctly
Let $q$ be the statement that Jules obtained the answer 2.
If Jules solved this problem correctly, then Jules obtained the answer 2 $(p →q)$
Jules obtained the answer 2 $(q)$
∴ Jules solved this problem correctly $(p)$
So the argument form is that
$p →q$
$q$
∴ $p$
Thus, the converse error has been made here.
