Question

In an examination there are three multiple choice questions and each question has 5 choices. Number of ways in which a student can fail to get all answer correct is …..

(a) 125 

(b) 124 

(c) 64 

(d) 63

Answer 1

(b) 124

Each question has 5 options in which 1 is correct 

So the number of ways of getting correct answer for all the three questions is 5³ = 125 

So the number of ways in which a student can fail to get all answer correct is < 125 (i.e.) 125 – 1 = 124