The graph shows, for each year of a 17-year period, the number of pairs of twins born in Region Z....
GMAT Graphics Interpretation : (GI) Questions
The graph shows, for each year of a 17-year period, the number of pairs of twins born in Region Z. In that time, the ratio of the number of twin births to the number of all births was essentially constant.
Select from each drop-down menu the option that creates the statement that is most strongly supported by the information provided.
Owning The Dataset
Table 1: Text Analysis
| Text Component | Literal Content | Simple Interpretation |
|---|---|---|
| Geographic Location | "Region Z" | The data covers a specific region called Region Z |
| Time Period | "17-year period" | The dataset spans 17 consecutive years |
| Data Measured | "the number of pairs of twins born" | Each value is the annual number of sets of twins born |
| Key Constraint | "the ratio of the number of twin births to the number of all births was constant" | Proportion of twins among all births stayed the same all years |
Table 2: Chart Analysis
| Chart Component | What's Shown | What This Tells Us |
|---|---|---|
| Chart Type | Line chart or series of data points | Visualizes trend in twin births per year |
| Years Shown | 1-17 (data given for years 1-16) | Full period covered; year 17 lacks data |
| Y-axis | Twin pairs (values approx. 200-650) | Number of twin pairs by year; large variation |
| Highest Value | Year 4: 627 pairs | Year 4 is the peak in twin births |
| Lowest Value | Year 16: 239 pairs | Year 16 has the fewest twin births recorded |
| Overall Pattern | Downward trend after year 4 | Twin births decline across most of the period after the peak |
Key Insights
Year 4 had the greatest number of births, since the highest number of twin pairs (627) were born that year and the twin-to-total-birth ratio was constant. Year 16 had the fewest twin births (239) among recorded years and thus likely the lowest total births. Year 17 was included in the chart but had no data. Among answer choices, Year 13 (355 pairs) represents the lowest available value. The data shows a clear trend: after an early peak, twin births (and thus all births) declined steadily in Region Z.
Step-by-Step Solution
Question 1: Year with Greatest Number of Births
Complete Statement:
Of the 17 years appearing in the graph, Year [BLANK 1] likely had the greatest number of births in Region Z
Breaking Down the Statement
- Statement Breakdown 1:
- Key Phrase: greatest number of births
_ Meaning: Identify the year with the highest total births.
_ Relation to Chart: The chart provides the number of twin births, not total births.
_ Important Implications: We need to use the relationship between twin births and total births to answer the question.
- Key Phrase: greatest number of births
- Statement Breakdown 2:
- Key Phrase: the ratio of the number of twin births to the number of all births was essentially constant
_ Meaning: Every year, the proportion of twin births to total births did not change.
_ Relation to Chart: Total births in each year are directly proportional to twin births in that year.
_ Important Implications: Finding the year with the most twin births gives us the year with the most total births.
- Key Phrase: the ratio of the number of twin births to the number of all births was essentially constant
- What is needed: The year with the highest number of twin births (and thus, the most total births).
Solution:
- Condensed Solution Implementation:
Use the given chart to locate the year with the maximum number of twin births, since total births are proportional. - Necessary Data points:
Chart data: for example, Year 1 (365 pairs), Year 4 (627 pairs), Year 17 (no bar, suggesting 0 or very few).
_ Calculations Estimations:
Review the twin births for answer choices: Year 1 (365), Year 4 (627), Year 17 (0). 627 is the maximum.
_ Comparison to Answer Choices:
Among the options, Year 4 has the highest number of twin births. Thus, Year 4 had the greatest number of total births.
FINAL ANSWER Blank 1: 4
Question 2: Year with Least Number of Births
Complete Statement:
and Year [BLANK 2] likely had the least number of births in Region Z
Breaking Down the Statement
- Statement Breakdown 1:
- Key Phrase: least number of births
_ Meaning: Identify the year with the lowest total births.
_ Relation to Chart: Twin births are given; due to constant ratio, lowest twin births means lowest total births.
- Key Phrase: least number of births
- Statement Breakdown 2:
- Key Phrase: Year 17
_ Meaning: There is no bar shown for Year 17 in the chart.
_ Relation to Chart: No data for Year 17 likely means zero or very few twin births, less than any year with a visible bar.
- Key Phrase: Year 17
- What is needed: The year among the options with the fewest twin births (and thus, the fewest total births).
Solution:
- Condensed Solution Implementation:
Compare the number of twin births for each answer choice, noting that no bar suggests the lowest value. - Necessary Data points:
Year 8 (434 pairs), Year 13 (355 pairs), Year 17 (no bar, likely less than Year 16's 239 pairs).
_ Calculations Estimations:
Year 17 has no visible bar, which likely means 0 or very few twin births, less than all other years.
_ Comparison to Answer Choices:
Among 8, 13, and 17, Year 17 has the lowest (potentially zero). Choose Year 17.
FINAL ANSWER Blank 2: 17
Summary
Since the ratio of twin to total births is constant, the years with highest and lowest twin births give the years with highest and lowest total births, respectively. Thus, Year 4 had the most, and Year 17 the least.
Question Independence Analysis
The questions are independent: one asks for the maximum and one for the minimum, requiring separate identification in the data. The solution for one blank does not directly provide the answer for the other.