During spring migration, a dragonfly traveled a minimum of 1,510 miles and a maximum of 4,130 miles between stopover locations....
GMAT Algebra : (Alg) Questions
During spring migration, a dragonfly traveled a minimum of 1,510 miles and a maximum of 4,130 miles between stopover locations. Which inequality represents this situation, where \(\mathrm{d}\) is a possible distance, in miles, this dragonfly traveled between stopover locations during spring migration?
1. TRANSLATE the problem information
- Given information:
- Minimum distance: 1,510 miles
- Maximum distance: 4,130 miles
- \(\mathrm{d}\) = a possible distance the dragonfly traveled
2. TRANSLATE each constraint into inequality form
- "Minimum of 1,510 miles" means: \(\mathrm{d \geq 1,510}\)
- "Maximum of 4,130 miles" means: \(\mathrm{d \leq 4,130}\)
3. INFER how to combine the constraints
- Since the dragonfly's distance must satisfy BOTH conditions at the same time, I need a compound inequality
- The distance must be at least 1,510 AND at most 4,130
- This gives us: \(\mathrm{1,510 \leq d \leq 4,130}\)
Answer: B. \(\mathrm{1,510 \leq d \leq 4,130}\)
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak TRANSLATE skill: Confusing the direction of inequality symbols with minimum/maximum language.
Students often think "minimum of 1,510" means \(\mathrm{d \leq 1,510}\), mixing up that minimum means the value must be AT LEAST that amount (so \(\mathrm{d \geq 1,510}\)). This fundamental translation error leads them to flip the inequality directions.
This may lead them to select Choice A (\(\mathrm{d \leq 1,510}\)) thinking it represents the minimum constraint.
Second Most Common Error:
Poor INFER reasoning: Not recognizing that both constraints must be satisfied simultaneously.
Students might correctly translate each piece individually but fail to combine them into a compound inequality. They might focus on just one constraint (usually the first one mentioned) and ignore the other.
This may lead them to select Choice A (\(\mathrm{d \leq 1,510}\)) by only considering the first number mentioned, or cause confusion leading to guessing.
The Bottom Line:
This problem tests whether students can accurately translate everyday language about ranges into mathematical notation. The key insight is remembering that "minimum" sets a lower bound (\(\mathrm{\geq}\)) while "maximum" sets an upper bound (\(\mathrm{\leq}\)), and both constraints work together to define a valid range.