An examination consists of 10 multiple-choice questions,in each of which a candidate has to deduce which one or five suggested answers is correct.A completely unprepared student guesses each answer completely randomly.What is the probability that this student gets 8 or more questions correct?Draw the appropriate moral!

In an examination there are 3 multiple choice questions and each question has 4 choices. Number of ways in which a student can fail to get all answers correct is

In an examination there are 3 multiple choice questions and each question has 4 choices. Number of ways in which a student can fail to get all Answers correct is

Each of five questions on a multiple chice examination has four choices,only one of which is correct.A student is attempting to guess the answers.The random variable X is the number of questions answered correctly.(iii)What is the probability that the student will get atleasdt one correct answer?

Each of five questions on a multiple chice examination has four choices,only one of which is correct.A student is attempting to guess the answers.The random variable X is the number of questions answered correctly.(i)What is the probability that the student will get exactly three answers correct?

The probability that a student knows the correct answer to a multiple choice question is 2/3 . If the student does not know the answer, then the student guesses the answer. The probability of the guessed answer being correct is 1/4 . Given that the student has answered the question correctly the probability that the student knows the correct answer is

A student answers a multiple choice question with 5 alternatives, of which exactly one is correct. The probability that he knows the correct answer is p, 0 lt p lt 1 . If he does not know the correct answer, he randomly ticks one answer. Given that he has answered the question correctly, the probability that he did not tick the answer randomly, is