On a multiple choice test, each question has five possible answers. a student does not know the answers to two questions, so he guesses. what is the probability that the student will get them both wrong?

The probability that he gets one of them wrong is 4/5 for there will only be one correct answer for every 4 wrong ones.

Now, to work out the probability that he gets BOTH wrong, we have to multiply the probability that he gets each of them wrong with each other. So:

4/5 x 4/5 = 16/25

So the probability that he gets BOTH wrong is 16/25 or 64% !

The answer is 6 weeks