Need legal help with this question that needs to be answered in an IRAC essay format

A person has a responsibility to return lost personal property to its rightful owner. ;

The question posed by this assignment is: What happens if those two rules collide? What if Alan finds Bart’s object and THEN Bart offers a reward for the return of the object? ;

Can Alan insist on the reward as a pre-condition for the return? Can Bart retract that reward because Alan had a pre-existing duty to return the property before the reward was offered? Or, do they both just sue each other to enforce their respective duties? Which of these alternatives (or something else) do you think will be enforced by a court? ;

Assume that both Alan and Bart live in the city of Boring, Oregon and that all events involved in this assignment occurred in that city.

An IRAC-style essay is appropriate for this assignment.
Please note that many of the best cases for this assignment are really old case