Answer
Invalid by the inverse error.
Work Step by Step
Inverse Error: $\forall x$ if $P(x)$ then $Q(x)$.
~$P(a)$ for a particular $a$.
$\therefore$ ~$Q(a)$. (invalid conclusion)
In this case P(x) is: x is a healthy person.
Q(x) is: x eats an apple a day.
a is Herbert.
