Bacterial Colony Growth Rates in Laboratory Study Bacterial Strain Growth Rate (colonies per hour) E. coli strain A 12.7 Bacillus...
GMAT Information and Ideas : (Ideas) Questions
Bacterial Colony Growth Rates in Laboratory Study
| Bacterial Strain | Growth Rate (colonies per hour) |
|---|---|
| E. coli strain A | 12.7 |
| Bacillus subtilis | 8.3 |
| S. aureus | 15.6 |
| P. aeruginosa | 6.1 |
| L. acidophilus | 4.9 |
A research team is investigating five different bacterial strains for their growth characteristics under controlled conditions. A graduate student conducting the analysis needs to compare growth rates across strains for her thesis research. Looking at the laboratory data, she observes that S. aureus demonstrates the highest multiplication rate at 15.6 colonies per hour. Among the remaining bacterial strains, which one shows a growth rate closest to 10.0 colonies per hour?
Which choice most effectively uses data from the table to answer the researcher's question?
E. coli strain A
Bacillus subtilis
P. aeruginosa
L. acidophilus
Step 1: Decode and Map the Passage
Part A: Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "Bacterial Colony Growth Rates in Laboratory Study" |
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| [Data Table with 5 bacterial strains and growth rates] |
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| "A research team is investigating five different bacterial strains for their growth characteristics under controlled conditions." |
|
| "A graduate student conducting the analysis needs to compare growth rates across strains for her thesis research." |
|
| "Looking at the laboratory data, she observes that S. aureus demonstrates the highest multiplication rate at 15.6 colonies per hour." |
|
| "Among the remaining bacterial strains, which one shows a growth rate closest to 10.0 colonies per hour?" |
|
Part B: Provide Passage Architecture & Core Elements
Visual Structure Map:
[RESEARCH CONTEXT] Laboratory study of bacterial growth rates → [DATA PRESENTATION] Table with 5 strains and growth rates → [RESEARCHER SITUATION] Graduate student analyzing for thesis
├── Observation 1: S. aureus highest (15.6)
└── Research Question: Which remaining strain closest to 10.0?
Main Point: A graduate student analyzing bacterial growth data has identified the highest-performing strain and now needs to determine which of the remaining strains has a growth rate closest to 10.0 colonies per hour.
Argument Flow: The passage establishes a laboratory study context, presents quantitative data on five bacterial strains, introduces a graduate student who is analyzing this data for her thesis, shows her initial finding about the highest performer, and concludes with the specific analytical question she needs to solve using the remaining data.
Step 2: Interpret the Question Precisely
What's being asked? We need to identify which answer choice most effectively uses the table data to answer the researcher's specific question about which remaining bacterial strain is closest to 10.0 colonies per hour.
What type of answer do we need? A bacterial strain selection that demonstrates proper use of the quantitative data to solve the researcher's analytical question.
Any limiting keywords? "Most effectively uses data from the table" - this means we must base our answer on the actual numerical values provided, and "remaining bacterial strains" means we exclude S. aureus since it was already identified as the highest.
Step 3: Prethink the Answer
- First, we need to exclude S. aureus since the question asks about "remaining" strains after it was identified as highest
- Second, we need to calculate the distance between each remaining strain's growth rate and the target of 10.0 colonies per hour
- Third, the correct answer should be the strain with the smallest absolute difference from 10.0
- Looking at our remaining options:
- E. coli strain A: \(\mathrm{12.7\, (distance = 2.7)}\)
- Bacillus subtilis: \(\mathrm{8.3\, (distance = 1.7)}\)
- P. aeruginosa: \(\mathrm{6.1\, (distance = 3.9)}\)
- L. acidophilus: \(\mathrm{4.9\, (distance = 5.1)}\)
- So the right answer should be Bacillus subtilis, which at 8.3 colonies per hour is only 1.7 away from the target of 10.0
E. coli strain A
✗ Incorrect
- E. coli strain A has a growth rate of \(\mathrm{12.7}\) colonies per hour
- While this uses table data, \(\mathrm{12.7}\) is \(\mathrm{2.7}\) units away from \(\mathrm{10.0}\), making it farther than the optimal choice
- What trap this represents: Students might choose this because \(\mathrm{12.7}\) is a "nice middle" number between the extremes, but they're not calculating actual distances from \(\mathrm{10.0}\)
Bacillus subtilis
✓ Correct
- Bacillus subtilis has a growth rate of \(\mathrm{8.3}\) colonies per hour
- This effectively uses the table data and represents the smallest distance from \(\mathrm{10.0}\) (only \(\mathrm{1.7}\) units away)
- This directly answers the researcher's question by identifying the closest remaining strain to her target value
P. aeruginosa
✗ Incorrect
- P. aeruginosa has a growth rate of \(\mathrm{6.1}\) colonies per hour
- This is \(\mathrm{3.9}\) units away from \(\mathrm{10.0}\), significantly farther than the best option
- Uses table data but doesn't provide the most effective answer to the research question
L. acidophilus
✗ Incorrect
- L. acidophilus has a growth rate of \(\mathrm{4.9}\) colonies per hour
- This is \(\mathrm{5.1}\) units away from \(\mathrm{10.0}\), the farthest distance from the target
- While it uses table data, it's the least effective choice for answering the researcher's question