Problem: The boy was waiting for Greg at the student center to return the sociology book he borrowed for tomorrow's test. But Greg was in the library and forgot it. Since the boy got a doctor'w appointment and need to get off campus soon, he had to figure a way to return the book as Greg might need it for the test. Solutions: 1. The boy can come back campus after a couple hours and return the book, but before that Greg might already need it for review. 2. The girl he was talking to can help him return the book to Greg in the library, but this may let her walk all across campus back and forth.