AlgebraVery hardMinimum sales for a target profit
Algebra practice question
A stall sells candles for $12 each. It costs $200 to hire the stall plus $7 to make each candle. What is the least number of candles the stall must sell for its profit to be at least $300?
Answer: 100
Profit = 12n − (200 + 7n) = 5n − 200. Then 5n − 200 ≥ 300 gives n ≥ 100.
Common wrong answers
- If you answered 25
- 25 solves 12n ≥ 300, ignoring costs entirely.
- If you answered 42
- 42 solves 12n − 200 ≥ 300, forgetting the $7 per candle.
- If you answered 60
- 60 solves 5n ≥ 300, forgetting the $200 hire cost.
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