How would an act utilitarian make a moral decision?

According to the theory of act utilitarianism, a person's actions are only moral if they achieve the best possible results in that specific situation. A simple example is copying from a classmate during school exams. Not putting personal effort and exploting somebody else's hard work to gain higher marks is not usually considered morally right. However, the best result possible is to obtain high marks in the test. Thus, if copying from somebody else's paper allows the student who copies to get higher grades than he would have, than the action is considered moral in an act utulitarianistic point of view.