Introducing Tilak, Satwik said, 'He is the grandson of my sister's only brother'. How is Satwik related to Tilak?

In a certain code language: 'A + B' means 'A is the daughter of B', 'A - B' means 'A is the brother of B', 'A x B' means 'A is the wife of B', 'A % B' means 'A is the father of B'. If 'Kartik + Vijay - Yash % Shreya x Rohan', how is Kartik related to Rohan?

In a certain code language: E + F means 'E is the husband of F' E - F means 'E is the mother of F' E × F means 'E is the wife of F' E ÷ F means 'E is the father of F' How is P related to T in the expression 'P × Q ÷ R - S + T'?