A gym requires members to earn at least 50 fitness points per week through cardio and strength training activities. Cardio...
GMAT Algebra : (Alg) Questions
A gym requires members to earn at least 50 fitness points per week through cardio and strength training activities. Cardio sessions are worth 6 points each and strength training sessions are worth 9 points each. The inequality \(6x + 9y \geq 50\) represents the weekly point requirement, where \(x\) is the number of cardio sessions and \(y\) is the number of strength training sessions. Which of the following is the best interpretation of \(9y\) in this context?
1. TRANSLATE the problem information
- Given information:
- \(\mathrm{6x + 9y \geq 50}\) is the inequality
- \(\mathrm{x}\) = number of cardio sessions
- \(\mathrm{y}\) = number of strength training sessions
- Cardio sessions = 6 points each
- Strength training sessions = 9 points each
2. TRANSLATE what each part of 9y means
- In the term \(\mathrm{9y}\):
- 9 is the coefficient = points earned per strength training session
- y is the variable = number of strength training sessions
3. INFER the meaning of the complete expression
- When we multiply: \(\mathrm{9 \times y}\) = (points per session) × (number of sessions)
- This gives us the total points earned from all strength training sessions combined
- So \(\mathrm{9y}\) represents the total number of points earned from strength training sessions
Answer: C
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak TRANSLATE skill: Students confuse the coefficient (per-session rate) with the entire expression (total points).
They see "9" in the expression \(\mathrm{9y}\) and think it represents the total points, leading them to select Choice B (The number of points earned from each strength training session) when they should recognize that \(\mathrm{9y}\) as a whole represents the total.
Second Most Common Error:
Poor TRANSLATE reasoning: Students mix up cardio and strength training terms.
They associate the wrong coefficient with the wrong activity type, thinking \(\mathrm{9y}\) relates to cardio instead of strength training. This leads them to select Choice D (The total number of points earned from cardio sessions).
The Bottom Line:
Success requires carefully translating each component of an algebraic expression back to its real-world meaning, recognizing that coefficient × variable gives a total quantity, not just the rate.