AlgebraMediumMinutes a heater can run within a temperature band
Algebra practice question
A room's temperature must be kept between 18°C and 24°C. A heater raises the temperature by 0.5°C per minute. Once the room reaches 18°C, for how many minutes can the heater keep running before the temperature exceeds 24°C?
Answer: 12
The temperature may rise by 24 − 18 = 6°C, which takes 6 ÷ 0.5 = 12 minutes.
Common wrong answers
- If you answered 3
- 3 comes from 6 × 0.5, multiplying instead of dividing.
- If you answered 6
- 6 is the allowed rise in degrees, not the minutes.
- If you answered 48
- 48 comes from 24 ÷ 0.5, heating from 0°C.
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