Answer:
Bob should give both groups a project that will help them reach a common goal.
Step-by-step explanation:
In Muzafer Sherif's study in Robbers Cave showed that two groups can unfairly judge another group based on competition. If the groups need to work together to reach a common goal, this will eliminate competition and will reduce conflict and hostility between the groups. The hope would be that the older group of workers and the younger group of workers could work together to reach a common goal and that in the end this would promote collaboration and respect among members of each group.