Biryani plates sold daily in a metro
Demand-side build with an occasion-frequency twist.
Estimate the number of biryani plates sold per day in a 10-million-person metro (restaurants + delivery + street, commercially sold only — home cooking excluded). The key structuring move: estimate eating-out occasions first, then biryani's share of them.
Who eats commercially
10M people; exclude very young children and strictly-home eaters → ~6M people in the commercial-food market.
Occasions
Office lunches, dinners out, delivery — averages to ~0.5 commercial meals/person/day (heavy for office-goers, light for homemakers/elderly) → 3M meals/day.
Biryani's share
Consistently a top-ordered dish; weight delivery higher → 8–10% of commercial meals → ~2.7 lakh plates.
Sanity check (supply side)
~15,000 biryani-serving outlets × ~20 plates/day ≈ 3 lakh — the two sides agree.
How to defend it
The interviewer will attack the 0.5 meals/day. Defend it as a weighted average: ~3M office-goers at ~0.8 (lunch + frequent delivery) and ~3M others at ~0.2. Always be ready to decompose any blended rate you state.