Final answer:
Eight justices concurred in the opinion of United States v. Dunn 480 U.S. 294 (1987).
Step-by-step explanation:
In the case of United States v. Dunn 480 U.S. 294 (1987),
eight justices concurred in this opinion. The majority of justices agreed on the decision, while there may have been separate concurring opinions that stressed different points of law or reasons for reaching the same conclusion. It is important to note that in a concurring opinion, a justice can agree with the majority opinion or only with the result.