If the students are in groups of exactly six when they visit the museum, the number visiting the museum must be 36, 42 or 48, because these are the only multiples of 6 between 30 and 50. If the bus partners are included in the groups and they are also students, then each group would consist of three students with their bus partners. If the bus partners are also students, but they do not go to the museum, but remain behind while their student partners visit the museum, then in all, 72, 84 or 96 students go to the museum, but only 36, 42 or 48 students actual visit it. If the bus partners are not students, they would be discounted from the groups, and the numbers just refer to the students.