Question

A test has 6 multiple choice questions, each with 4 alternatives. What is the probability of guessing 5 or more questions correctly?

Answer 1

0.0009765625‬

Explanation:

Each multiple choice question has 4 equally likely alternatives.

Hence, probability of guessing the right answer for 1 question is
`\[(1)/(4)\]` = 0.25

Hence, probability of guessing the wrong answer is
`\[(1)/(4)\]` = 0.75

The probability of guessing 5 or more questions correctly = probability of guessing 5 questions correctly & 1 question wrong + probability of guessing 6 questions correctly

=
`\[0.25^(5)*0.75+0.25^(6)\]`

= 0.000732421875 + 0.000244140625

= 0.0009765625‬