In an examination there are three multiple choice questions and each question has four choice.

Since each question has 4 options 

i.e there are 4 choices or 4 ways to answer a question  

∴ Number of ways to answer 3 questions is 4 × 4 × 4 = 64

Out of 64 ways, there is only one way which has all the answer correct. 

So, number of ways in which a student fails to get all answer correct is 64 − 1 = 63 ways.