Where Do People Get Most of Their Medical Information? Source Percent of those surveyed Doctor 63% Internet 13% Magazines/brochures 9%...
GMAT Problem-Solving and Data Analysis : (PS_DA) Questions
Where Do People Get Most of Their Medical Information?
| Source | Percent of those surveyed |
|---|---|
| Doctor | 63% |
| Internet | 13% |
| Magazines/brochures | 9% |
| Pharmacy | 6% |
| Television | 2% |
| Other/none of the above | 7% |
The table above shows a summary of 1,200 responses to a survey question. Based on the table, how many of those surveyed get most of their medical information from either a doctor or the Internet?
865
887
912
926
1. TRANSLATE the question requirements
- Given information:
- Total surveyed: 1,200 people
- Doctor: \(63\%\)
- Internet: \(13\%\)
- What we need: Number of people who get information from doctor OR Internet
2. INFER the mathematical approach
- Since each person can have only one primary source, "either...or" means we add the percentages
- We need to find what percentage get information from doctor OR Internet, then apply that to 1,200
3. Add the relevant percentages
- Doctor OR Internet = \(63\% + 13\% = 76\%\)
4. SIMPLIFY by calculating the final answer
- \(76\%\) of 1,200 people = \(0.76 \times 1,200 = 912\) (use calculator)
Answer: C. 912
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak INFER skill: Students might misunderstand what "either...or" means in this context and try to use more complex probability rules instead of simple addition.
Some students think they need to account for overlap between categories, not realizing that each person can only select one primary source. This leads to confusion about whether to add, subtract, or use intersection formulas, causing them to get stuck and guess randomly.
Second Most Common Error:
Poor TRANSLATE execution: Students correctly identify they need to add percentages but make arithmetic errors in either the addition (\(63\% + 13\%\)) or the final multiplication.
For example, they might calculate \(63\% + 13\% = 75\%\) instead of \(76\%\), leading to \(75\% \times 1,200 = 900\), which isn't among the choices. Or they might get \(76\%\) correct but calculate \(76\% \times 1,200\) incorrectly. This leads to confusion and guessing among the available choices.
The Bottom Line:
This problem tests whether students can correctly interpret survey data language ("either...or") and systematically apply percentage calculations. The key insight is recognizing that survey categories are mutually exclusive, making this a straightforward addition and multiplication problem.
865
887
912
926