Steps you need to do in order to solve the problem: (a) figure out which conic section is related to the locus of a fixed-order interference maxima from two point sources; (b) if there are three point sources, relate the positions of the interference maxima to the intersection points of conic sections; (c) construct some of those conic sections; (d) based on the constructed conic sections, reconstruct the positions of the light sources.
Please submit the solution to this problem via e-mail to physcs.cup@gmail.com. The next hint for the Problem 5 will be published at 13:00 GMT, 16th April 2023, together with the next updates of the intermediate results.