A rectangular wall is partitioned into five rectangular parts as shown below. If three different colours are available and no two adjacent parts may be painted with the same colour, in how many different ways can the wall be painted?           | UPSC CAPF 2026 Q No 68

Accepted Answer: (A) 16

Topic Covered: Quantitative Aptitude and Reasoning

Key Concept: Mathematical relationships, counting and logical analysis

Treat each rectangular part as a vertex and each shared boundary as an adjacency relation. Counting valid three-colour assignments under the no-adjacent-same-colour rule gives the official-key answer.

The key is to apply the central fact, formula, definition or relationship tested in the question and then eliminate alternatives that do not satisfy it.