Rule 1: All members of a group are responsible for the group's work
When working in groups, each member shall contribute equally and all members shall be capable of accounting for the whole solution.
Many assignments are performed in groups of two or more students. In any work in a group, cooperation within the group is of course permitted. Every member of the group must contribute to the work. All members of the group must be able to give an individual account of the entire assignment and the entire solution, unless otherwise stated in the official course syllabus or course memo.