'A # B' means 'A is the husband of B'
'A @ B' means 'A is the wife of B'
'A & B' means 'A is the mother of B'
'A % B' means 'A is the father of B'

If 'J @ I % H # G & F', then how is I related to F?

Let's decode the given expression step-by-step from left to right:
J @ I → J is the wife of I (So, I is the husband, i.e., Male).

I % H → I is the father of H.

H # G → H is the husband of G (So, G is the wife of H).

G & F → G is the mother of F.

Let's trace the relationship from F to I:

G is the mother of F.

H is the husband of G, so H is the father of F.

I is the father of H.

Since I is the father of F's father (H), I is the father's father (grandfather) of F.