Profit margin in permille
A store wants its margin as a whole per-mille number: how much of each minor unit of revenue survives as profit.
- Margin is (revenue - cost) × 1000 ÷ revenue, rounded down.
- A revenue of zero or less has no defined margin: return 0.
- A loss yields a negative margin.
profit_margin(revenue: int, cost: int) → int
Where you start
def profit_margin(revenue: int, cost: int) -> int:
Worked examples
| Call | Result |
|---|---|
profit_margin(1000, 600) | 400 |
profit_margin(1000, 1000) | 0 |
profit_margin(1000, 1200) | -200 |
profit_margin(0, 100) | 0 |
Hint
Subtract the cost from revenue, scale by 1000, divide by revenue.
Reference solution in Python
def profit_margin(revenue: int, cost: int) -> int:
if revenue <= 0:
return 0
return (revenue - cost) * 1000 // revenue