In order to better control traffic at a certain busy intersection, a study was conducted to determine how many vehicles...
GMAT Graphics Interpretation : (GI) Questions
In order to better control traffic at a certain busy intersection, a study was conducted to determine how many vehicles passed through the intersection during various times of day and what trajectories they took. For each possible trajectory (combination of direction from which a vehicle entered the intersection and direction to which it exited the intersection), the graph shows the number of vehicles passing through the intersection during a certain hour.
Select from the drop-down menus the options that create the statement that most accurately reflects the information provided.
Owning The Dataset
Table 1: Text Analysis
| Text Component | Literal Content | Simple Interpretation |
|---|---|---|
| Study Purpose | In order to better control traffic at a certain busy intersection | Traffic patterns were studied to improve intersection management |
| Study Methodology | A study was conducted to determine how many vehicles passed through the intersection during various times | Researchers counted vehicles at different times |
| Trajectory Definition | Combination of direction from which a vehicle entered the intersection and direction to which it exited | Trajectory = entry direction + exit direction |
| Time Period | During a certain hour | Data covers only a single hour |
| Data Representation | The graph shows the number of vehicles passing through the intersection during a certain hour for each route | A chart displays vehicle counts for each entry-exit pair |
Table 2: Chart Analysis
| Chart Component | What's Shown | What It Indicates |
|---|---|---|
| Graph Type | Horizontal bar chart with 12 bars (each = a direction pair) | Each bar represents a trajectory (entry\(\rightarrow\)exit combination) |
| Bar Values | Bars range from 30 to 98 vehicles | Traffic volume varies greatly by trajectory |
| Highest Bar | West \(\rightarrow\) East: 98 vehicles | Most common single route |
| Lowest Bar | West \(\rightarrow\) South: 30 vehicles | Least common route |
| Pattern For South Entry | South\(\rightarrow\)North: 97, South\(\rightarrow\)East: 95, South\(\rightarrow\)West: 96 | Vehicles entering from South distribute almost evenly |
| Pattern For West Entry | West\(\rightarrow\)North: 45, West\(\rightarrow\)East: 98, West\(\rightarrow\)South: 30 | High variation, very few go West\(\rightarrow\)South |
| Totals By Entry Direction | South: 288; North: 256; East: 186; West: 173 | South is the busiest entry |
Key Insights
Southbound entries dominate the intersection, both in number and balance—nearly equal numbers head north, east, and west. The most frequent path overall is West to East (98 vehicles), while West to South is used the least (30 vehicles), suggesting strong directional trends. These patterns indicate that traffic management efforts should focus on accommodating heavy flows from the South, and possibly investigating the low usage of the West to South path.
Step-by-Step Solution
Question 1: Direction with Greatest Number of Vehicles Entering
Complete Statement:
During the hour, the greatest number of vehicles entered the intersection from the _____
Breaking Down the Statement
- Statement Breakdown 1:
- Key Phrase: During the hour
- Meaning: The question concerns a specific time period of one hour.
- Relation to Chart: All data in the chart are totals for this hour.
- Important Implications: Only use the vehicle counts provided for this one hour.
- Statement Breakdown 2:
- Key Phrase: greatest number of vehicles entered the intersection
- Meaning: We need to determine which direction received the most entering vehicles.
- Relation to Chart: Add up the number of vehicles entering from each direction.
- Important Implications: Compare the entry totals for each direction.
- What is needed: Which direction had the largest total number of vehicles entering the intersection during the hour.
Solution:
- Condensed Solution Implementation:
Sum the vehicle entries for each direction and determine which is greatest. - Necessary Data points:
North entries: 95 + 83 + 78 = 256. East entries: 65 + 62 + 59 = 186. South entries: 97 + 95 + 96 = 288. West entries: 45 + 98 + 30 = 173. - Calculations Estimations:
North: 256, East: 186, South: 288, West: 173. - Comparison to Answer Choices:
South (288) \(\gt\) North (256) \(\gt\) East (186) \(\gt\) West (173). South is greatest.
FINAL ANSWER Blank 1: south
Question 2: Exit Direction with Greatest Number from the South
Complete Statement:
and among those vehicles entering the intersection from that direction, the greatest number of vehicles exited the intersection to the _____
Breaking Down the Statement
- Statement Breakdown 1:
- Key Phrase: among those vehicles entering the intersection from that direction
- Meaning: Focus on vehicles that entered from the direction found in question 1 (south).
- Relation to Chart: Only look at exits for vehicles that entered from the south.
- Statement Breakdown 2:
- Key Phrase: the greatest number of vehicles exited
- Meaning: Of the south entries, find which exit direction had the most vehicles.
- Relation to Chart: Compare the exit counts for vehicles entering from the south.
- What is needed: Of the vehicles that entered from the south, which exit direction had the highest count.
Solution:
- Condensed Solution Implementation:
Compare values for vehicles that entered from south and exited north, east, or west. - Necessary Data points:
South\(\rightarrow\)North: 97. South\(\rightarrow\)East: 95. South\(\rightarrow\)West: 96. - Calculations Estimations:
97 (north), 96 (west), 95 (east). - Comparison to Answer Choices:
North has the largest number of exiting vehicles among those that entered from the south.
FINAL ANSWER Blank 2: north
Summary
The south direction had the largest number of vehicles entering the intersection (288). Of those, most exited to the north direction (97).
Question Independence Analysis
The second question depends on the answer to the first since it asks about vehicles from the direction identified in question 1; therefore, the questions are not independent.