Any time more than one person works together to solve a problem it is usually more efficient.
Problem solving becomes easier when people work together.
I am able to learn more, and truly understand things better. When I work with myself I always question everything I do. There have been many times throughout the semester that if I hadn't been working with a group I may have given up on the assignment. If I am clueless on something a partner may be an expert on it. If you are not as strong in a subject, or do not fully understand the concept of a idea, your partner can help you understand and explain it to you.