describe and confirm a procedure of using a real coin to cr

) describe and confirm a procedure of using a real coin to create a virtual fair die

2) A student is to answer a multiple choice question that has four possible answers. The probability that the student knows that answer is 0.8 and the probability that the student doesn\'t know the answer and guesses is 0.2; \"guessing \" means the student picks one of the four possible answers at random, If the student answers correctly, what is the probability that the student really knew the answer?

Solution

Let A= event that the student knows the answer ; B= event that the student answers correctly

Given:P(A) = 0.8 ; P(B)= .8+.2*.25 =.85

If the student answers correctly, the probability that the student really knew the answer = P(Al B) = P(A&B)/P(B)=P(A)=0.8