Question:The minimum value of x is 12 more than one-sixth of a number n. Which inequality shows the possible values...
GMAT Algebra : (Alg) Questions
The minimum value of x is 12 more than one-sixth of a number n. Which inequality shows the possible values of x?
- \(\mathrm{x \leq \frac{n}{6} + 12}\)
- \(\mathrm{x \geq \frac{n}{6} + 12}\)
- \(\mathrm{x \leq \frac{n}{6} - 12}\)
- \(\mathrm{x \geq \frac{n}{6} - 12}\)
1. TRANSLATE the problem information
- Given information:
- "The minimum value of x is 12 more than one-sixth of a number n"
- What this tells us:
- We need to convert this English phrase into mathematical notation
- "One-sixth of a number n" = \(\frac{\mathrm{n}}{6}\)
- "12 more than" means we add 12
- So "12 more than one-sixth of n" = \(\frac{\mathrm{n}}{6} + 12\)
2. INFER what "minimum value" means
- Key insight: If something is the minimum value of x, then x can be equal to that value OR greater than that value
- This means we need the "greater than or equal to" symbol: ≥
- Therefore: \(\mathrm{x} \geq \frac{\mathrm{n}}{6} + 12\)
3. Match with answer choices
Looking at the options, our inequality \(\mathrm{x} \geq \frac{\mathrm{n}}{6} + 12\) matches choice (B).
Answer: B
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak INFER skill: Confusing "minimum" with "maximum"
Students often think that if something is the "minimum value," then x must be less than or equal to that value. This incorrect reasoning leads them to choose \(\mathrm{x \leq \frac{n}{6} + 12}\) instead of \(\mathrm{x \geq \frac{n}{6} + 12}\).
This may lead them to select Choice A (\(\mathrm{x \leq \frac{n}{6} + 12}\))
Second Most Common Error:
Poor TRANSLATE execution: Misinterpreting "12 more than"
Some students get confused about the order of operations in the phrase "12 more than one-sixth of n" and incorrectly translate it as \(\frac{\mathrm{n}}{6} - 12\) instead of \(\frac{\mathrm{n}}{6} + 12\).
This may lead them to select Choice D (\(\mathrm{x \geq \frac{n}{6} - 12}\))
The Bottom Line:
This problem tests whether you can accurately translate English to math notation AND understand the logical meaning of "minimum value." The key breakthrough is recognizing that a minimum value establishes a lower bound, meaning the variable must be greater than or equal to that bound.