Two students at a university were to take a mid-term test in statistics. The night before the test the two students went to a party in another town and did not get back to the university in time for the test. They gave as an excuse to the lecturer concerned that they had had a flat tyre and asked if they could re-take the test. The lecturer agreed and set a new test and sent the two to separate rooms to take it. The first question (on one side of the paper) was worth five marks, and they answered it easily. Then they turned the paper over and found the second question, worth 95 marks: ‘Which tyre was it?' What was the probability that both students would say the same thing?