A student is to answer a multiple choice question that has five possible answers. The probability that the student knows the answer is .90 and the probability that the student does not know the answer and guesses is .10 ; ""guesses"" means the student picks one of

means that he picks any of the 5 choices at random

Step-by-step explanation:

"guesses" means that the student will pick at random any of the 5 choices that he has with the hope to select the right one. Then we are assuming that any of the 5 choices are equally likely to be the correct one , so there is no answer that is closest to be the right one ( we do not have any information that can judge whether any answer is more likely to be the right one with respect to the others).