If they were simple, you wouldn't learn nearly as much. You want to have to fight with them, and you do NOT want someone to give you too much of a direct hand, because you learn most effectively by fighting with them. So I want to guide your fight and nothing more.Thank you for your comment.
As a student these kind of problems for me are not so simple.
But your solution doesn't track with theirs. Look at what they have done in section (i) very carefully and match that up, step by step, with yours. Notice that if R=2Ω, then their inner TPN network is the same as the one in the problem you are working.The attached is an example exactly similar to the Q-1. I have used that method for solving Q-1.