There are 48 members in the school's debate club. In a recent survey, club members were asked whether they plan...
GMAT Problem-Solving and Data Analysis : (PS_DA) Questions
There are 48 members in the school's debate club. In a recent survey, club members were asked whether they plan to participate in the upcoming regional tournament. The survey found that \(\frac{3}{8}\) of members surveyed indicated they plan to participate. Based on this survey, which of the following is the best estimate of the total number of debate club members who plan to participate in the tournament?
- 6
- 18
- 24
- 36
6
18
24
36
1. TRANSLATE the problem information
- Given information:
- Total debate club members: 48
- Survey result: "3 out of every 8 members plan to participate"
- What this tells us: The participation rate is \(\frac{3}{8}\) of all members
2. INFER the solution approach
- This is a proportion problem: if 3 out of every 8 members participate, then we expect the same rate across all 48 members
- Strategy: Multiply the total membership by the participation rate
- Mathematical setup: \(48 \times \frac{3}{8}\)
3. SIMPLIFY the calculation
- \(48 \times \frac{3}{8} = (48 \times 3) \div 8\)
- \(= 144 \div 8\)
- \(= 18\)
Answer: B (18)
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak TRANSLATE skill: Students misinterpret "3 out of every 8" and think it means only 3 people total will participate, or they confuse the survey sample size with the participation rate.
Instead of recognizing that \(\frac{3}{8}\) is a rate to be applied to all 48 members, they might think the answer is simply 3, or they might try to work with 8 as if it's the total number surveyed rather than the denominator of a rate.
This may lead them to select Choice A (6) by thinking 3 people from the survey means 6 people total, or causes confusion and guessing.
Second Most Common Error:
Inadequate SIMPLIFY execution: Students set up the problem correctly as \(48 \times \frac{3}{8}\) but make arithmetic errors in the calculation.
Common mistakes include calculating \(48 \times 3 = 124\) instead of 144, or dividing incorrectly. Some students might also try to convert \(\frac{3}{8}\) to a decimal first and make rounding errors.
This may lead them to select Choice C (24) or Choice D (36) depending on their specific calculation error.
The Bottom Line:
This problem tests whether students can recognize survey data as a rate that applies proportionally to a larger population, then execute the arithmetic correctly. The key insight is seeing "3 out of 8" as a fraction that scales up to the full membership.
6
18
24
36