Problem Solving
Problem Solving
Problem Solving presents multi-step puzzles: scheduling, seating, route planning, or resource allocation. The exam tests whether you can impose constraints systematically rather than guess.
Core rules
- Define the goal and list every constraint explicitly. A constraint you do not write down is a constraint you will break.
- Work backwards when the final state is fixed and the start is open.
- Eliminate options that violate a hard constraint; do not try to build the full solution at once.
- Draw a grid, timeline, or table. Spatial and ordering puzzles become manageable when externalised.
- Check the finished solution against every constraint, not just the ones you remembered.
Worked example
Three friends - Aoife, Brian, and Ciara - each have a different appointment on Monday, Tuesday, or Wednesday. Aoife is not on Monday. Brian is on Tuesday. Ciara is not on Wednesday. Who is on Monday? Brian = Tuesday. Remaining days: Monday and Wednesday for Aoife and Ciara. Ciara cannot be Wednesday, so Ciara = Monday. Aoife = Wednesday. Answer: Ciara.
Traps
- Ignoring a negative constraint ("not on Monday") because it is easy to overlook.
- Assuming a unique solution when the puzzle allows several; the question may ask for what must be true.
- Changing the goal mid-solution.
- Failing to re-check after a late deduction invalidates earlier work.
- Spending too long on one puzzle; but do not abandon a nearly complete grid.