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put this solution on YOUR website!I will assume that both of them will pass the exam ONLY IF their answers are the same (in which case it will convince the professor that they really had a flat!). Student 1 has 4 choices, and student 2 has also 4 choices. Hence there are 4*4 = 16 ways for the 2 students to give their answers. Of these, there are only 4 ways that both of them could give the same answer. Thus the probability that the students pass is 4/16, or 1/4.