Many tortoises hibernate each year when the weather gets cold and the plants they eat are in very short supply...
GMAT Graphics Interpretation : (GI) Questions
Many tortoises hibernate each year when the weather gets cold and the plants they eat are in very short supply or no longer available. A tortoise that is about to hibernate needs to have built up enough fat reserves in order to survive through winter until the spring. For a specific tortoise species, the chart shows the arithmetic mean ratio of carapace (upper shell) length to body weight prior to hibernation, as well as the minimum length-to-weight ratio that the tortoise needs in order to ensure the likelihood of surviving until spring.
Select from each drop-down menu the option that creates the most accurate statement based on the information provided.
Owning The Dataset
Table 1: Text Analysis
| Text Component | Literal Content | Simple Interpretation |
|---|---|---|
| Hibernation trigger | Many tortoises hibernate each year when the weather gets cold and the plants they eat are in very short supply or no longer available. | Tortoises hibernate in cold weather and food shortages. |
| Survival requirement | A tortoise that is about to hibernate needs to have built up enough fat reserves in order to survive through winter until the spring. | Tortoises require enough body fat before hibernation to survive winter. |
| Chart content description | For a specific tortoise species, the chart shows the arithmetic mean ratio of carapace (upper shell) length to body weight prior to hibernation | The chart shows average shell length-to-weight ratios before hibernation. |
| Minimum weight definition | as well as the minimum length-to-weight ratio that the tortoise needs in order to ensure the likelihood of surviving until spring. | The chart also shows the minimum weight needed to survive. |
| Carapace definition | carapace (upper shell) | Carapace means the shell on the tortoise's back. |
Table 2: Chart Analysis
| Chart Component | What's Shown | What This Tells Us |
|---|---|---|
| Chart type | Means and minimum ratios of carapace length to body weight (two lines) | We can compare average vs minimum weight needed for survival. |
| X-axis | Carapace length in millimeters (80mm to 280mm) | Represents tortoise shell sizes. |
| Y-axis | Body weight in grams (values ranging from ~100g to ~2900g) | Shows how heavy the tortoises are at each shell size. |
| Mean line | Higher than the minimum line for all shell sizes | Most tortoises weigh more than the minimum needed. |
| Minimum line | Lower bound representing survival cutoff | Tortoises below this line may not survive hibernation. |
| Gap between lines | Increases as shell size increases | Larger tortoises have a bigger margin above minimum survival weight. |
| Data at 220mm | Mean weight explicitly shown (1500g); minimum value not in table but appears on chart | At 220mm, minimum can be estimated using chart trend; table has a gap. |
Key Insights
For this species, both average and minimum weights increase as shell size grows, meaning larger tortoises need to be heavier overall. The gap between the average (mean) and minimum survival weights widens as tortoises get larger, suggesting a greater buffer or variability. At carapace length 220mm, the mean weight is 1500g, but the specific minimum weight is missing in the table, though it can be estimated from the chart. This demonstrates that most tortoises are well above the minimum threshold needed for survival, especially as they grow larger.
Step-by-Step Solution
Question 1: Minimum Weight Required for Hibernation Survival at 220mm Carapace Length
Complete Statement:
In order to ensure the likelihood of surviving the winter, a tortoise of that specific species discussed with a carapace length of 220 millimeters should weigh at least [BLANK 1] grams before hibernation.
Breaking Down the Statement
- Statement Breakdown 1:
- Key Phrase: ensure the likelihood of surviving the winter
- Meaning: The focus is on survival through hibernation; the tortoise must meet a minimum weight threshold.
- Relation to Chart: We must use the minimum weight trend or line on the chart for this species.
- Important Implications: The required value is the minimum weight, not the mean or maximum.
- Statement Breakdown 2:
- Key Phrase: carapace length of 220 millimeters
- Meaning: We're interested in tortoises with exactly 220mm length shells.
- Relation to Chart: Find 220mm on the x-axis and look for the associated minimum weight.
- Important Implications: We must estimate or interpolate the minimum value at this specific length.
What is needed: The minimum weight (in grams) necessary for a 220mm tortoise to survive hibernation.
Solution:
- Condensed Solution Implementation:
Identify or estimate the minimum weight at 220mm using the data table and the minimum weight line on the chart. - Necessary Data points:
From the chart: At 200mm, minimum weight is 1250g; at 240mm, it's 1900g. The mean at 220mm is 1500g. The minimum value at 220mm is not given directly but can be estimated from the minimum line between these two points. - Calculations Estimations:
Notice that as carapace length increases, the difference between mean and minimum weight increases (at 200mm it's 300g; at 240mm it's 500g). Interpolate or read the chart: at 220mm, the minimum weight line appears to be about 1000g. - Comparison to Answer Choices:
Answer options: 500, 1000, 1500, 2000. Estimated value is 1000g, which matches an option.
FINAL ANSWER Blank 1: 1000
Question 2: Difference Between Mean and Minimum Weight at 220mm
Complete Statement:
which is approximately [BLANK 2] grams less than the mean pre-hibernation weight of tortoises of the same carapace length and species.
Breaking Down the Statement
- Statement Breakdown 1:
- Key Phrase: grams less than the mean pre-hibernation weight
- Meaning: The difference between the mean weight and the minimum weight at 220mm.
- Relation to Chart: Use the mean and minimum values at 220mm from the chart or data.
- Statement Breakdown 2:
- Key Phrase: same carapace length and species
- Meaning: Both weights to be compared are for 220mm tortoises of this species.
- Relation to Chart: Ensures we are making the correct comparison at the right data point.
What is needed: How many grams less the minimum safe weight is, compared to the mean weight, for 220mm tortoises.
Solution:
- Condensed Solution Implementation:
Subtract the minimum weight value at 220mm (from the previous answer) from the mean weight value at 220mm. - Necessary Data points:
Mean weight at 220mm: 1500g (from table). Minimum weight: 1000g (from Blank 1). - Calculations Estimations:
Difference = 1500g (mean) - 1000g (minimum) = 500g. - Comparison to Answer Choices:
Options: 500, 1000, 1500, 2000. 500g matches the calculated difference.
FINAL ANSWER Blank 2: 500
Summary
To ensure survival through hibernation, a 220mm carapace tortoise should weigh at least 1000g, based on interpolated chart values. This is 500g less than the mean pre-hibernation weight for that size. The minimum was estimated by recognizing the increasing difference between mean and minimum weights as carapace length increases and selecting the closest matching answer choice.
Question Independence Analysis
Blank 2 depends on the answer to Blank 1, since it requires the minimum weight value found in Blank 1 to determine how much less it is compared to the mean at the same size. The questions are not independent.