Students Anu, Binu, Chinki and Debu study one subject each from among Geography. History, English or Physics whose books are placed in a sequence on the bookshelf. Chinki studies English book. History book is adjacent to the Physics book. Anu does not study the book adjacent to the book studied by Chinki. English book is the only book in between the History and Geography books. What subject book does Anu study?

Physics

We are given that :- 

1. Chinki studies the English book.

2. History is adjacent to the Physics book.

3. Anu does not study the book adjacent to the one studied by Chinki.

4. The English book is the only book in between the History and Geography books.

From equation 2 ,

As There is two possible arrangements Either ( History , Physics ) OR ( Physics , History )

From equation 4 ,

Possible arrangements are either ( History , English , Geography ) or ( Geography , English , History ) .

As it is clearly mentioned that , Anu does not study the book adjacent to one studied by Chinki , That means Anu does not study the book of History and geography .

So, Book studied by Annu is of Physics.