Arrange the following words into a sentence
Theater-mitkommen-du-ins-?
me: Kommst du ins Theater mit?
Book: Kommst du mit ins Theater?
Why is the mit after the pronoun here?
Arrange the following words into a sentence
Theater-mitkommen-du-ins-?
me: Kommst du ins Theater mit?
Book: Kommst du mit ins Theater?
Why is the mit after the pronoun here?
Both solutions, yours and the book's solution are correct German. It's as so often a matter of emphasis of the question.
Kommst Du ins Theater mit?
The emphasis is on coming along. This is less common and the same possibly could be done also by stressing mit in the other version.
Kommst Du mit ins Theater?
The emphasis is on to the theater.
The prefix/preposition mit is a bit special as it may switch roles rather freely. It's completely up to you if you want to emphasize on the verb (prefix) or the adverbial (preposition).
So both answers are okay. It's not specifically about questions either.
Sie kommt am Abend ins Theater mit.
Sie kommt am Abend mit ins Theater.