(1) W % L × T × Y ÷ X - W is mother of L, L is sister of T and T is sister of Y and Y is son of X. So, X and W are couples and their children are L, T and Y.
(2) W + L × T × Y ÷ X - W is father of L, rest all same as in (1), so X is mother of Y.
(3) X + L × T × Y ÷ W - Same as (2) with X and W interchanged. So, X is father of Y.
(4) W $ X + L + Y + T - W is wife of X, X is father of L, L is father of Y, Y is father of T. So, X is grand father of Y and hence the ANSWER.
(5) W % X + T × Y ÷ L - W is mother of X, X is father of T, T is sister of Y, Y is son of L. So, X is father of Y.