Q46. 46. Let p + q = 10, where p, q are integers. Value-I = Maximum value of p × q when p, q are positive integers. Value-II = Maximum value of p × q when p ≥- 6, q ≥ -4.
Which one of the following is correct?
Detailed Solution
Given p + q = 10, where p and q are integers. Value-I: Maximum value of p × q when p, q are positive integers. For a fixed sum, the product of two numbers is maximized when the numbers are as close to each other as possible.
Since p + q = 10, and p, q are positive integers, the closest integers are p=5 and q=5. Their product is 5 * 5 = 25. So, Value-I = 25. Value-II: Maximum value of p × q when p ≥ -6, q ≥ -4.
Again, p + q = 10. The product pq can be written as p(10-p). This is a quadratic function of p, f(p) = 10p - p², which represents a downward-opening parabola. The maximum value occurs at the vertex, where p = -10 / (2 * -1) = 5.
If p=5, then q = 10 - 5 = 5. These values satisfy the constraints p ≥ -6 and q ≥ -4. At p=5, q=5, the product pq = 5 * 5 = 25. Let's check the boundary conditions: If p = -6, then q = 10 - (-6) = 16.
This satisfies q ≥ -4. Product = (-6) * 16 = -96. If q = -4, then p = 10 - (-4) = 14. This satisfies p ≥ -6. Product = 14 * (-4) = -56. The maximum product within the given constraints is 25.
So, Value-II = 25. Comparing Value-I and Value-II: Value-I = 25 Value-II = 25 Therefore, Value-I = Value-II. This question tests understanding of number properties and optimization within given constraints.
More General Mental Ability Questions
Q66. 66. If NO is coded as 210, NOT is coded as 4200 and NOTE is coded as 21000, then how is NOTES coded?...
AQ67. 67. If FRANCE is coded as 654321 and GERMANY is coded as 9158437, then how is YEMEN coded?...
DQ49. 49. Let x be a real number between 0 and 1. Which of the following statements is/are correct? I. x² ...
AQ35. 35. A natural number N is such that it can be expressed as N = p + q + r, where p, q, and r are dist...
CQ36. 36. Three prime numbers p, q, and r, each less than 20, are such that p – q = q – r. How many distin...
AMore from UPSC 2025 CSAT
Q1. Which one of the following statements best reflects the central idea conveyed by the passage?...
DQ2. With reference to the above passage, the following assumptions have been made: I. Higher education i...
AQ3. Which one of the following statements best reflects the crux of the passage?...
BQ4. With reference to the above passage, the following assumptions have been made: I. The food manufactu...
BQ5. What is the maximum value of n such that 7 × 343 × 385 × 1000 × 2401 × 77777 is divisible by 35^n ?...
BAce UPSC with AI-powered Practice
LearnPro's test series adapts to your weak topics and shows real analytics.
Explore Courses →