A landscape designer is creating a garden layout using two types of flower beds: triangular beds and hexagonal beds. The...
GMAT Algebra : (Alg) Questions
A landscape designer is creating a garden layout using two types of flower beds: triangular beds and hexagonal beds. The total area covered by all flower beds is 156 square feet. The equation \(12\mathrm{x} + 18\mathrm{y} = 156\) represents this situation, where \(\mathrm{x}\) is the number of triangular beds and \(\mathrm{y}\) is the number of hexagonal beds. Which statement is the best interpretation of \(18\) in this context?
Each hexagonal bed covers 18 square feet.
The number of hexagonal beds is 18.
Each triangular bed covers 18 square feet.
The number of triangular beds is 18.
1. TRANSLATE the equation components
- Given equation: \(12\mathrm{x} + 18\mathrm{y} = 156\)
- Variables defined:
- \(\mathrm{x}\) = number of triangular beds
- \(\mathrm{y}\) = number of hexagonal beds
- 156 = total area in square feet
2. INFER what coefficients represent in context
- In equations like \(\mathrm{ax} + \mathrm{by} = \mathrm{c}\) where \(\mathrm{c}\) is a total:
- The coefficient tells us the contribution per unit
- 12 is multiplied by \(\mathrm{x}\) (triangular beds) → 12 = area per triangular bed
- 18 is multiplied by \(\mathrm{y}\) (hexagonal beds) → 18 = area per hexagonal bed
3. TRANSLATE back to answer the question
- The question asks about the meaning of 18
- Since 18 is the coefficient of \(\mathrm{y}\) (hexagonal beds), it represents the area each hexagonal bed covers
- Therefore: 18 = area per hexagonal bed = 18 square feet per hexagonal bed
Answer: A
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak TRANSLATE skill: Students confuse coefficients with variables or constants in the equation.
They might think 18 represents the actual number of hexagonal beds (confusing it with the variable \(\mathrm{y}\)) or associate it with triangular beds instead of hexagonal beds. This conceptual mix-up about what different parts of the equation represent leads them to select Choice B (The number of hexagonal beds is 18) or Choice C (Each triangular bed covers 18 square feet).
The Bottom Line:
This problem tests whether students can correctly interpret the structural meaning of coefficients in real-world linear equations - specifically that coefficients represent "per unit" contributions when the equation shows a total.
Each hexagonal bed covers 18 square feet.
The number of hexagonal beds is 18.
Each triangular bed covers 18 square feet.
The number of triangular beds is 18.