“Teacher: You have the same mistakes as the person next to you. How could that happen?”

There’s a school joke about the teacher who suspects a student of cheating:
 
Teacher: You have the same mistakes as the person next to you. How could that happen?
Student: We have the same teacher.
 
The joke has been cited in print since at least 2011.
 
     
Google Books
The Best Jokes I’ve Heard (Volume 2)
By Douglas Blankenship
Bloomington, IN: AuthorHouse
2011
Pg. 368:
THE SAME MISTAKES IN THE DICTATION
Teacher to Vovochka:
- Vovochka, both you and your neighbor Sidorova have the same mistakes in the dictation. Why?
- Well, both of us have the same teacher,
 
Twitter
Tricia ♡
‏@Triciaaa_B
teacher: You have exactly the same mistakes in your test as the guy who sat next to you.me: That’s not so strange, we have the same teacher!
6:34 AM - 31 Oct 2011
 
Google Books
Michael Winner’s Hymie Joke Book
By Michael Winner
London: Biteback Publishing,
2012
Pg. ?:
When asked to explain how he made exactly the same mistakes as his neighbour, Jacob replies, “It’s because we have the same teacher.”
 
Twitter
PEACE SIGN ✌️
‏@Evans_Ehirim
Teacher:Jhonny, both you and your neighbor Santa have
the same mistakes in the dictation.Why?
Jhonny: Well, both of us have the same teacher
1:35 PM - 15 Sep 2012
 
Twitter
Miguel
‏@Meinaaaaaard
When your teacher asks you why you and your friend have the same mistakes, tell her you have the same teacher. =))
6:15 PM - 24 Jan 2016
 
Twitter
Afgan Jalebiii ❤ 👑 ❤
‏@Imshonaaa
In a test💁
Teacher: how’s it possible that u have made the same mistakes as your classmate?😬
Me: mam, coz we have the same teacher💯
1:38 AM - 18 May 2016
 
Twitter
Rahul Rao
‏@rahulrrao
Teacher asks how it’s possible that my classmate has the same mistakes as I have.
Classmate says, “We have the same teacher”
6:26 AM - 3 Dec 2016
 
Reddit—Jokes
Teacher: You have the same mistakes as the person next to you, how could that happen?
submitted January 16, 2017 by TheUberStick
Me: We have the same teacher.