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The table provides data about 12 different Persian rugs currently available for sale by a rug dealer. For each rug, the data includes the number of knots per square inch (KPSI) in the yarn, which can be assumed consistent throughout the rug. There are 12 inches in a foot, so a rug having a width of \(\mathrm{x}\) feet and a length of \(\mathrm{y}\) feet has an area equal to \((12^2)\mathrm{x}\mathrm{y}\) square inches.
| Type | Age | Width (ft) | Length (ft) | KPSI | Price |
|---|---|---|---|---|---|
| Kashan | 20 | 10 | 14 | 212 | $3,950 |
| Kashan | 20 | 10 | 12 | 162 | $3,852 |
| Kashmar | 20 | 8 | 9 | 162 | $3,920 |
| Kerman | 20 | 10 | 14 | 280 | $3,530 |
| Isfahan | 25 | 10 | 15 | 158 | $3,930 |
| Kashan | 25 | 9 | 15 | 158 | $3,762 |
| Kashmar | 25 | 10 | 13 | 158 | $3,763 |
| Kashmar | 25 | 10 | 12 | 158 | $3,762 |
| Mashad | 25 | 10 | 12 | 158 | $3,762 |
| Isfahan | 35 | 10 | 14 | 158 | $3,470 |
| Isfahan | 35 | 10 | 14 | 158 | $3,470 |
| Ardabil | 45 | 9 | 13 | 112 | $3,952 |
For each of the following statements, select T if it is true based on the information provided; otherwise select F.
The rug with the greatest KPSI has more than 5,500,000 knots.
The median KPSI of the 4 newest rugs is 162.
The median length of Kashan rugs is equal to the median length of Kashmar rugs.
Let's start by understanding what we're working with in this rug dataset. The table contains information about 12 different rugs with details about their type, age, dimensions (length and width in feet), and KPSI (knots per square inch).
Key insights from our initial review:
Total knots = KPSI × length × width × 144 (where \(144 = 12^2\) to convert sq ft to sq inches)This quick data understanding will help us efficiently analyze each statement without getting lost in unnecessary calculations.
Statement 1 Translation:
Original: "The rug with the greatest KPSI has more than 5,500,000 knots"
What we're looking for:
In other words: Does the rug with the most knots per square inch have more than 5.5 million knots in total?
Let's approach this efficiently by sorting the data:
1. Let's sort by KPSI (in descending order)
This immediately shows us the rug with the highest KPSI at the top of our sorted list - a Kerman rug with 280 KPSI, measuring 10×14 feet.
Now, we need to determine if this rug has more than 5,500,000 knots total. Rather than calculating the exact number, we can use a quick approximation:
Area in square inches = \(10 \times 14 \times 144 = 20,160\) sq inches
Total knots ≈ \(280 \times 20,160 \approx 5,644,800\) knots
Since \(5,644,800 > 5,500,000\), this statement is T.
Teaching Callout: Notice how sorting instantly identified our target rug! Instead of manually comparing all 12 KPSI values, a simple sort command gave us the answer immediately. Also, we used approximation when precise calculation wasn't necessary - this saves valuable time on the GMAT.
Statement 2 Translation:
Original: "The median KPSI of the 4 newest rugs is 162"
What we're looking for:
In other words: If we arrange the KPSI values of the 4 youngest rugs, is the middle value (median) 162?
Again, sorting is our most efficient approach:
1. Let's sort by Age (in ascending order)
After sorting, we can immediately see the 4 newest rugs (all 20 years old) at the top of our list. Their KPSI values are: 212, 162, 162, and 280.
To find the median of these 4 values, we arrange them: 162, 162, 212, 280
Since we have an even number of values, the median is the average of the middle two:
Median = \(\frac{162 + 212}{2} = \frac{374}{2} = 187\)
Since \(187 \neq 162\), this statement is F.
Teaching Callout: Sorting by age made it incredibly easy to identify our subset of interest! Instead of scanning the entire table for the newest rugs, they were all grouped together at the top. Once we had our relevant data subset, finding the median became straightforward.
Statement 3 Translation:
Original: "The median length of Kashan rugs equals the median length of Kashmar rugs"
What we're looking for:
In other words: Is the middle value of Kashan rug lengths the same as the middle value of Kashmar rug lengths?
The most efficient approach is to group the rugs by type:
1. Let's sort by Type
After sorting, all rugs of the same type appear together, making it easy to analyze each group:
For the Kashan section (3 rugs), the lengths are 14, 12, and 15 feet.
The median of 3 values is simply the middle value = 14 feet.
For the Kashmar section (3 rugs), the lengths are 9, 13, and 12 feet.
The median of these 3 values is the middle value = 12 feet.
Since \(14 \neq 12\) feet, this statement is F.
Teaching Callout: Sorting by type created visual groups that made our analysis much faster! We didn't need to write out the values separately or scan back and forth through the table. Also, when you have just 3 values, the median is simply the middle value - no calculation needed.
After analyzing all three statements:
The answer is therefore A: Statement 1 ONLY is true.
Remember: In table analysis questions, how you approach the data is often more important than the calculations themselves. Sorting is your superpower - it instantly transforms complicated searches into simple visual scans!
The rug with the greatest KPSI has more than 5,500,000 knots.
The median KPSI of the 4 newest rugs is 162.
The median length of Kashan rugs is equal to the median length of Kashmar rugs.