Direct speech: He said,"I shall unlock the secrets of their success".
Indirect speech(book answer): He said that he should unlock the secrets of their success.
Indirect speech(my answer): He said that he would unlock the secrets of their success.
I think my answer is correct I have two reason for that-
Shall is used with first person pronouns (I,we) and will with second and third person pronouns.
(In my answer there is "he" as a subject so there should be "would".
If it suggest any obligation than we use "will" with first person and "shall" with second and third person pronoun.
So in original question there is no such obligation on speaker so there should be would instead of should.
So correct me if i am wrong?
Direct speech: I wrote,"I shall visit him tomorrow".
Indirect speech(book answer): I wrote that I would visit him next day.
I have same confusion in this sentence.