Six countries in a certain region sent a total of 75 representatives to an international congress, and no two countries...
GMAT Data Sufficiency : (DS) Questions
Six countries in a certain region sent a total of \(75\) representatives to an international congress, and no two countries sent the same number of representatives. Of the six countries, if Country A sent the second greatest number of representatives, did Country A send at least \(10\) representatives?
- One of the six countries sent \(41\) representatives to the congress
- Country A sent fewer than \(12\) representatives to the congress
Understanding the Question
Let's break down what we're asked to determine:
- 6 countries sent a total of 75 representatives
- No two countries sent the same number
- Country A sent the second greatest number
- Question: Did Country A send at least 10 representatives?
This is a yes/no question. We need to determine definitively either:
- YES: Country A sent \(\geq 10\) representatives, or
- NO: Country A sent \(< 10\) representatives
Let's label the countries by their ranking:
- Country 1: Most representatives
- Country A: Second most representatives
- Countries 3, 4, 5, 6: The remaining four countries in descending order
So we have: \(\mathrm{Country\ 1} > \mathrm{Country\ A} > \mathrm{Country\ 3} > \mathrm{Country\ 4} > \mathrm{Country\ 5} > \mathrm{Country\ 6}\)
Analyzing Statement 1
What Statement 1 Tells Us
One of the six countries sent 41 representatives to the congress.
Testing Different Scenarios
Let's test which country could have sent 41 representatives:
Case 1: Country 1 sent 41
- Country A \(< 41\) (since Country A ranks second)
- The other 5 countries together sent: \(75 - 41 = 34\) representatives
- Since Country A is the largest among these 5 countries, Country A could theoretically be anywhere from 7 to 33
- Could Country A = 9? Yes! Example: 41, 9, 8, 7, 6, 3 (total = 75)
- Could Country A = 10? Yes! Example: 41, 10, 9, 8, 5, 2 (total = 75)
- Since Country A can be both \(< 10\) and \(\geq 10\), we get different answers (NO and YES)
Case 2: Country A sent 41
- Country 1 \(> 41\), so Country 1 \(\geq 42\)
- But \(42 + 41 = 83\), which already exceeds our total of 75
- This is impossible!
Case 3: One of Countries 3-6 sent 41
- If any lower-ranked country sent 41, then Country A \(> 41\)
- This means Country A \(\geq 42\), which is definitely \(\geq 10\)
- This would give us answer YES
Conclusion for Statement 1
Since different scenarios give different answers (Case 1 allows both YES and NO, while Case 3 gives only YES), Statement 1 is NOT sufficient.
[STOP - Not Sufficient!] This eliminates choices A and D.
Analyzing Statement 2
Now let's forget Statement 1 completely and analyze Statement 2 independently.
What Statement 2 Provides
Country A sent fewer than 12 representatives, so Country A \(\leq 11\).
Testing the Critical Values
Since Country A \(\leq 11\), let's test if Country A could be 9, 10, or 11:
Can Country A = 9? (This would give answer NO)
- If Country A = 9, then Country 1 \(\geq 10\)
- Example distribution: 40, 9, 8, 7, 6, 5 (total = 75) ✓
- All different ✓, Country A is second ✓
- Answer: NO
Can Country A = 10? (This would give answer YES)
- If Country A = 10, then Country 1 \(\geq 11\)
- Example distribution: 35, 10, 9, 8, 7, 6 (total = 75) ✓
- All different ✓, Country A is second ✓
- Answer: YES
Conclusion for Statement 2
Since Country A can be both \(< 10\) (giving answer NO) and \(\geq 10\) (giving answer YES), Statement 2 is NOT sufficient.
[STOP - Not Sufficient!] This eliminates choice B.
Combining Both Statements
Combined Information
From both statements together:
- One country sent 41 representatives
- Country A \(< 12\) (so Country A \(\leq 11\))
Key Insight
Given Statement 2, Country A can only be 9, 10, or 11. The question becomes: does knowing "one country sent 41" narrow this down to a single answer?
Testing Combined Scenarios
Since Country A \(\leq 11\), and one country sent 41, that country must be Country 1 (the highest-ranking country).
Let's construct examples with Country 1 = 41:
Example 1 - Country A = 11:
Distribution: 41, 11, 10, 7, 4, 2
- Check: All different ✓, Total = 75 ✓, Country A is second ✓
- Country A = 11 \(\geq 10\)
- Answer: YES
Example 2 - Country A = 10:
Distribution: 41, 10, 9, 8, 5, 2
- Check: All different ✓, Total = 75 ✓, Country A is second ✓
- Country A = 10 \(\geq 10\)
- Answer: YES
Example 3 - Country A = 9:
Distribution: 41, 9, 8, 7, 6, 4
- Check: All different ✓, Total = 75 ✓, Country A is second ✓
- Country A = 9 \(< 10\)
- Answer: NO
Why the Statements Together Aren't Sufficient
Even with both statements, we've proven that Country A can still be either \(< 10\) or \(\geq 10\), giving different answers to our yes/no question. The constraint that one country sent 41 doesn't eliminate any of our possibilities for Country A (9, 10, or 11).
[STOP - Not Sufficient!] This eliminates choice C.
The Answer: E
The statements together are not sufficient because we can construct valid scenarios where:
- Country A sent 9 representatives (answer NO)
- Country A sent 10 or 11 representatives (answer YES)
Since we cannot determine a definitive YES or NO answer even with both statements, the answer is E.
Answer Choice E: "The statements together are not sufficient."