Prove that if $a+b+c$ divides $abc$, then $a+b+c$ must be composite.

I have seen another post for this same question but it never got an answer. Since I am fairly new, I can't comment on other's posts, therefore I am creating a new one. The question states: If a, b, and c are positive integers, prove that if $(a + b + c) | (a*b*c)$, then $a+b+c$ is composite.

I do not really know how to approach this.

The link to the post with the same question is: Proving that $a+b+c $ is composite knowing it divides $abc$

Suppose, by way of contradiction, that $a+b+c=p$ is prime. (It is greater than $1$, so that's the only way it can fail to be composite.) Then we have $a<p$, $b<p$ and $c<p$, so $p$ doesn't divide any of the three. Therefore, it does not divide their product, either.

Does that work for you?