Question

In an examination there are 3 multiple choice questions and each question has 4 choices. If a student randomly selects answer for all the three questions. What is the probability that the student will not answer all the 3 questions correctly ?

Answer 1

Probability of selecting a correct choice for a question = \(\frac{1}{4}\)

(∵ Out of 4 choices only one is correct)

∴ Probability of answering all the three questions correctly = \(\frac{1}{4}\)x \(\frac{1}{4}\)x\(\frac{1}{4}\) = \(\frac{1}{64}\)

⇒ Probability of not answering all the three questions correctly = 1 - \(\frac{1}{64}\) = \(\frac{63}{64}\).