Conspiracy in the exam hall

It's the big day. It's the . You enter the exam hall boasting with confidence, having never studied as hard before. Inside your mind, you know the exam is going to be a piece of cake. 

This is your exam. Don't worry. The fur aren't real. Its chocolate chips. 

Yeah, the hard part about the exam is the chocolate chips part. It's about having to sit in that chair and table enduring 2 to 3 hours. But the question is going to be easy. As easy as cake. You wished your friends and classmates(notice the and, they are probably different) good luck...

Dammit! I knew ''good luck'' had another meaning!

...And sat down. You sit down, and see that its 1 minute before the cake gets delivered. You then called the pizza to deliver 2 sets to your home while you enjoy the air-con and television. Since, why not?

No wait, we were talking about exams. 

By the way, i want to eat this.

Back to the exam, you sit down and wait for the cake to deliver. The invigilator goes to you and...

GIVES YOU A GIANT COCKROACH!

Alright just fooling with you. Thats a cake. Probably. I searched cake on Google images. 

You were given the paper. The invigilator looks at the time, asks the hall to check the paper. Okay, no problems. All is good. One answer sheet, one question booklet. No printing errors, brain is clear. Not feeling hungry, not going for the toilet for any moment. The invigilator gives the signal to start! Time to dissect and eat the cake!!

NOO!! I DON'T WANNA EAT THIS!! SPARE ME...

See, i told you its a cake. 

Flip! The exam is easy! You have more trouble catching Pokemon than solving these!

You look to your left and right. HAH! People looked troubled. You're going to end up the top of your class...  

''Hmm... The catch rate of Moltres is about...''

Whoops. You quickly turn back to your paper. You don't want to be accused of cheating just because your looking left and right.

...

After that arduous 2 to 3 hours, you feel satisfied. Your friends and classmates were discussing... And you knew all the answers. Even the teacher joined in the conversation and confirmed your answers were all correct. You can proudly say to everyone that you aced the exams...

-----------------

The results were back. And you opened the result slip... WHAT! YOU FAILED!

Impossible! The question paper had all your workings, and they were all correct. There must be a mistake! You phoned the markers. You complained. Requested to see the marked paper. Miraculously, they allowed you to see your answers...

DUN DUN DUN!! WHY HAVE YOU FAILED? 

You answered the solution for question 1 on the rough paper page, Q2 on Q1, Q 3 on Q2.... etc etc...