Question 66
Every one of six pupils attends exactly two of four hobby groups. There are no pupils attending the same two hobby groups. Each hobby group is open every day. During some consecutive days, every one of these six pupils has attended one of her/his hobby group. It has been observed that each of these days each hobby group has been attended by either one or two of the pupils. Moreover, for any chosen two days, there has been a pupil who has attended different hobby groups during these two days.
Find the largest number of the days for which the situation described above is possible.
Find the largest number of the days for which the situation described above is possible.