A plant in a greenhouse needs to reach at least 24.0°C for optimal growth. If the current temperature is 21.2°C,...

1. TRANSLATE the problem information

• Given information:
  • Current temperature: \(21.2°\mathrm{C}\)
  • Target temperature needed: \(24.0°\mathrm{C}\) (for optimal growth)
  • Need to find: temperature increase required

• What this tells us: We need to find how much the temperature must rise from its current value to reach the optimal value.

2. TRANSLATE what "temperature increase" means

• Temperature increase = Final temperature - Starting temperature
• Temperature increase = Target temperature - Current temperature
• So we need: \(24.0°\mathrm{C} - 21.2°\mathrm{C}\)

3. SIMPLIFY the calculation

• \(24.0 - 21.2 = 2.8\)
• Therefore, a temperature increase of \(2.8°\mathrm{C}\) is needed

Answer: A. 2.8

Why Students Usually Falter on This Problem

Most Common Error Path:

Weak SIMPLIFY execution: Making arithmetic errors during decimal subtraction

Students might rush through the subtraction \(24.0 - 21.2\) and make calculation mistakes, such as getting \(3.2\) instead of \(2.8\) due to borrowing errors or misaligning decimal places.

This may lead them to select Choice C (\(3.2\))

The Bottom Line:

While this problem tests a straightforward concept, students can still stumble on the basic arithmetic. The key insight is recognizing that "temperature increase" simply means finding the difference between where you want to be and where you are now.