Break the problem into a demand-side estimation: global population → number of households → annual detergent usage per household. Use reasonable assumptions and round numbers to simplify calculations, and state your assumptions clearly.
Pro tip: Start by clarifying whether the question refers to household laundry detergent only or includes industrial/institutional use, and whether it's by volume or weight. This shows you think about scope and units before diving into numbers.
Ask if the estimate should cover household consumers only or also commercial/industrial laundry, and whether the answer should be in liters, kilograms, or dollars.
Use ~8 billion people and an average household size of 4, giving ~2 billion households. Adjust for regions with different laundry habits if needed.
Assume an average household does 3-5 loads per week, using ~50-100 ml of detergent per load. Calculate annual usage per household (e.g., 4 loads/week * 52 weeks * 75 ml ≈ 15.6 liters/year).
Multiply households by annual per-household usage: 2 billion * 15.6 liters ≈ 31.2 billion liters per year. Convert to weight if needed (density ~1 kg/L, so ~31 million metric tons).
Compare with known market data (e.g., global laundry detergent market ~$100B, average price ~$3/L implies ~33 billion liters). Adjust assumptions if the estimate seems off.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.