The Night Watchman's Dilemma

The barrel whose surrounding floor smells of water is the water barrel. The other is the oil barrel. The earlier spills left behind scent-based identification markers. Rajan simply uses his sense of smell on the floor — no light needed.

Puzzles like this one test whether solvers look for complexity when the answer is sitting right in the problem statement. All the information needed is already given — the floor around each barrel carries the smell of its contents from the earlier spill. Step 1: The problem states that a worker spilled drinking water near the water barrel earlier that week. Step 2: It also states that engine oil was spilled near the oil barrel. Both spills remain on the floor. Step 3: Rajan kneels and sniffs near one barrel — it smells of water. This means the water spill is near this barrel, identifying it as the water barrel. Step 4: The other barrel, by elimination, is the oil barrel. No light, no tasting, no opening required. Step 5: The sensory information — smell — was already present in the environment. Rajan simply needed to use it. Step 6: This is confirmed without ambiguity: a water-smelling floor means water was stored there, and an oil-smelling floor means oil was stored there. Key Insight: The best puzzles hide the solution inside the problem description itself. The spill detail is not flavour text — it is the answer. Training yourself to treat every detail in a problem as potentially load-bearing is the core skill this puzzle teaches.