Problem Solving is the fifth quest of Chapter 3, "Home Sweet Slum", in Final Fantasy VII Remake, taking place in the Sector 7 Slums. While Tifa Lockhart gives Cloud Strife a tour of the Sector 7 Slums, the two help the Neighborhood Watch and fight monsters. After Cloud obtains the Iron Blade from the Weapon Store, Tifa encourages him to talk to Wymer at the neighborhood watch office.
Follow the marker to Wymer, who is located in the southwest end of Sector 7's Residential Area. After a quick conversation with him, Cloud and Tifa talk to Chadley, who gives the two the Assess Materia and offers a sidequest, "Chadley's Report". This can be done while also completing the objectives of other sidequests.
Four sidequests become available: "Chadley's Report", "Rat Problem", "Nuisance in the Factory", and "Lost Friends". They can be tracked on the map to find their destination. "Lost Friends" is a simple non-combat sidequest, but initiating it allows the player to do it in the background. "Rat Problem" and "Nuisance in the Factory" are combat sidequests, which are relatively quick to complete, and doing so allows the player to achieve the objective of "Chadley's Report".
Before attempting the combat sidequests, it is a good idea to upgrade currently possessed weapons. "Rat Problems" is the closer of the two and allows the player to obtain the Cleansing Materia, but both it and "Nuisance in the Factory" are worth completing. After completing one of these sidequests, Tifa will also tell Cloud that Barret likely has his money ready. However, it is better to simply complete all sidequests now. Completing "Rat Problem" also unlocks "On the Prowl" while completing "Nuisance in the Factory" unlocks "Just Flew In from the Graveyard".
Completing all sidequests unlocks "Alone at Last", which affects both dress mechanics and affection mechanics that come into play during Chapter 9, "The Town That Never Sleeps", and Chapter 14, "In Search of Hope", respectively. If no sidequests were completed, default options for Tifa will be selected in both cases; if all were, completing "Alone at Last" unlocks options in both instances.
If the player travels to the eastern side of the map at some point, it will lead to "A Job Well Done", in which a cutscene commences as Johnny is taken out; this will immediately lead into "Shinra Reacts", a main scenario quest.
Hard mode tips
The sidequest "On the Prowl" must be completed to obtain the manuscript, Way of the Fist Vol. IV, for Tifa. Beyond this, many of the sidequests can be skipped if desired, though they present a good opportunity to level up materia as the later chapters become more challenging.