او بعد از کلاس برای من نوشت و گفت که جواب سوال در کتاب است.

A careful, standard pronunciation would be:

u ba'd az kelâs barâye man nevesht va goft ke javâb-e so'âl dar ketâb ast.

A few notes:

• او = u
• بعد از = ba'd az
• برای من = barâye man
• نوشت = nevesht
• و = va in careful speech, but often sounds like o in conversation
• گفت = goft
• که = ke
• جوابِ سوال = javâb-e so'âl
  The -e is important in pronunciation, even though it is usually not written.
• در کتاب است = dar ketâb ast

In everyday spoken Persian, it would often sound more like:

u ba'd az kelâs barâm nevesht o goft ke javâb-e so'âl tuye ketâbe.

It can mean either he or she.

Persian third-person singular pronouns do not show gender. So:

• او = he or she
• او ... نوشت = he wrote or she wrote

You understand the gender only from context, if it is known at all.

بعد از کلاس means after class or after the class, depending on context.

Breakdown:

• بعد از = after
• کلاس = class

It appears early in the sentence because Persian often puts time expressions before the main part of the clause:

• او بعد از کلاس برای من نوشت
• literally: he/she after class to me wrote

That is a very normal Persian order.

In this sentence, برای من نوشت is best understood as wrote to me.

Literally:

• برای = for / to
• من = me
• نوشت = wrote

With نوشتن (to write), Persian can mark the recipient in different ways. In real usage:

• برای من نوشت can mean wrote to me
• به من نوشت can also mean wrote to me

Here, because it is followed by و گفت که..., the meaning is clearly that the person sent me a written message and said that the answer is in the book.

So a natural English translation is:

• He/She wrote to me after class and said...

Yes, literally it does mean wrote and said.

But in natural English, we usually smooth that out a little:

• wrote to me and said...
• sent me a message saying...

In Persian, this structure is completely normal. It means the person wrote something and, in that writing, said that the answer is in the book.

که introduces the content of what was said. Here it works like that in English:

• گفت که... = said that...

So:

• گفت که جواب سوال در کتاب است
• said that the answer to the question is in the book

In many everyday sentences, که can be omitted after گفت:

• گفت جواب سوال در کتاب است

That is also natural, especially in speech. Including که is clear and standard.

Persian normally prefers subject–object/complements–verb order, so the verb often comes at the end of its clause.

Here is the structure:

• او بعد از کلاس برای من نوشت
• he/she after class to me wrote

Then:

• و گفت که جواب سوال در کتاب است
• and said that the answer to the question in the book is

The important point is:

• نوشت ends the first clause
• گفت is the main verb of the second clause
• است ends the clause introduced by که

This final-position tendency for verbs is one of the most important sentence patterns in Persian.

Because Persian, like English, can keep the verb in the present if the statement is still true.

So:

• گفت که جواب سوال در کتاب است
• He/She said that the answer is in the book

This suggests that the answer is still in the book now.

If you said:

• گفت که جواب سوال در کتاب بود
• He/She said that the answer was in the book

that would sound more like a past situation, or at least it would present the embedded statement as past.

So the present است is completely natural here.

Because Persian usually puts the main noun first and the modifying noun after it.

So:

• جوابِ سوال
• literally: answer of the question
• natural English: the answer to the question

The head noun is جواب (answer), and سوال (question) comes after it as a modifier.

This is a very common Persian pattern:

• کتابِ استاد = the teacher’s book
• درِ خانه = the door of the house
• جوابِ سوال = the answer to the question

Because Persian uses the ezafe sound, usually pronounced -e (or -ye after vowels), but it is often not written in normal spelling.

So جواب سوال is pronounced:

• javâb-e so'âl

That little -e links the two nouns.

This is one of the first things English-speaking learners need to get used to: Persian script often leaves out short vowels and also usually leaves ezafe unwritten.

So although you see:

• جواب سوال

you pronounce and understand it as:

• جوابِ سوال
• the answer to the question

Because there is no definite direct object that needs را.

A few points:

• او is the subject
• برای من is a prepositional phrase
• جواب سوال is the subject of است inside the reported clause
• در کتاب is another prepositional phrase

In other words, جواب سوال is not the direct object of گفت. It is the subject of the clause جواب سوال در کتاب است.

That is why you do not get:

• جواب سوال را در کتاب است ❌

If the sentence had a real direct object, then را might appear.

Because Persian has no definite article like English the.

A bare noun can be understood as:

• the book
• a book
• sometimes a more general noun meaning

The exact meaning comes from context.

So:

• در کتاب است

can literally be something like is in book, but natural English requires an article, so in context we translate it as is in the book.

If Persian wants to mark indefiniteness clearly, it often uses -ی:

• کتابی = a book / some book

But here کتاب is just a plain noun whose definiteness is understood from context.

A natural colloquial version would be:

اون بعدِ کلاس برام نوشت و گفت جوابِ سؤال توی کتابه.

Some common spoken changes are:

• او → اون
• برای من → برام
• و → often pronounced o
• که may be omitted
• در → توی
• است → -ه

So the formal/written sentence:

او بعد از کلاس برای من نوشت و گفت که جواب سوال در کتاب است.

becomes something like:

اون بعدِ کلاس برام نوشت و گفت جوابِ سؤال توی کتابه.

Both are correct; the first is more standard/written, and the second is more conversational.