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UPSC Prelims 2024CSATLogical ReasoningData Sufficiency

Q59. A Question is given followed by two Statements I and
II. Consider the Questions and the Statements. Question : What are the values of m and n , where m and n are natural numbers? Statement-I : m + n > mn and m > n . Statement-II : The product of m and n is 24.

Which one of the following is correct in respect of the above Question and the Statements?

A. The Question can be answered by using one of the Statements alone, but cannot be answered using the other Statement alone
B. The Question can be answered by using either Statement alone
C. The Question can be answered by using both the Statements together, but cannot be answered using either Statement alone✓ Correct
D. The Question cannot be answered even by using both the Statements together

Detailed Solution

✓ Correct Answer: Option C

We need to find unique natural numbers m and n. **Statement I: m + n > mn and m > n.** Let's test some natural number pairs where m > n: - If m=2, n=1: 2+1 = 3, 2*1 = 2. Since 3 > 2, (2,1) is a possible pair.

- If m=3, n=1: 3+1 = 4, 3*1 = 3. Since 4 > 3, (3,1) is a possible pair. Since there are multiple possibilities, Statement I alone is insufficient. **Statement II: The product of m and n is 24 (mn = 24).** Possible pairs of natural numbers (m,n): - (1,24), (2,12), (3,8), (4,6), (6,4), (8,3), (12,2), (24,1).

Since there are multiple possibilities, Statement II alone is insufficient. **Combining Statement I and Statement II:** We need to find a pair (m,n) from the list in Statement II that satisfies m + n > mn and m > n.

From Statement II, mn = 24. So the condition m + n > mn becomes m + n > 24. Let's check the pairs from Statement II that also satisfy m > n: 1. (24,1): m+n = 25. Is 25 > 24? Yes.

So (24,1) is a solution. 2. (12,2): m+n = 14. Is 14 > 24? No. 3. (8,3): m+n = 11. Is 11 > 24? No. 4. (6,4): m+n = 10. Is 10 > 24? No. Only the pair (24,1) satisfies both conditions.

Thus, m=24 and n=1 are uniquely determined. Therefore, both statements together are sufficient to answer the question. This question tests data sufficiency and number properties.

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