Maths : Basic Numeracy

Q 38 / 370

UPSC CSE Prelims 2025

Let x be a real number between 0 and 1. Which of the following statements is/are correct?

  1. Figure for the question: Let x be a real number between 0 and 1. Which of the following statements is/are correct?…
  2. Figure for the question: Let x be a real number between 0 and 1. Which of the following statements is/are correct?…

Select the correct answer using the code given below:

EXPLANATION

Correct Option (3)

Given that x is a real number such that 0 < x < 1.

Statement I: Explanation figure for the question: Let x be a real number between 0 and 1. Which of the following statements is/are correct?… (which represents x² < x)

  • Consider the inequality x² < x.
  • Rearranging, we get x² - x < 0.
  • Factoring out x, we have x(x - 1) < 0.
  • Since 0 < x < 1, x is a positive number.
  • Also, for 0 < x < 1, (x - 1) is a negative number.
  • The product of a positive number and a negative number is always negative.
  • Therefore, x(x - 1) < 0 is true for all real numbers x between 0 and 1.
  • Hence, Statement I is correct.

Statement II: Explanation figure for the question: Let x be a real number between 0 and 1. Which of the following statements is/are correct?… (which represents x < √x)

  • Consider the inequality x < √x.
  • Since x is between 0 and 1, both x and √x are positive. We can square both sides without changing the inequality direction.
  • Squaring both sides yields x² < x.
  • This is the same inequality as Statement I, which has already been proven to be correct for 0 < x < 1.
  • Alternatively, consider an example: if x = 0.25, then √x = √0.25 = 0.5. Here, 0.25 < 0.5, which means x < √x holds true.
  • Hence, Statement II is correct.

Since both Statement I and Statement II are correct, the appropriate option is (3).

Incorrect Options:

  • Option (1) "I only" is incorrect because Statement II is also correct.
  • Option (2) "II only" is incorrect because Statement I is also correct.
  • Option (4) "Neither I nor II" is incorrect because both statements are correct.
Explanation figure for the question: Let x be a real number between 0 and 1. Which of the following statements is/are correct?… Explanation figure for the question: Let x be a real number between 0 and 1. Which of the following statements is/are correct?… Explanation figure for the question: Let x be a real number between 0 and 1. Which of the following statements is/are correct?… Explanation figure for the question: Let x be a real number between 0 and 1. Which of the following statements is/are correct?… Explanation figure for the question: Let x be a real number between 0 and 1. Which of the following statements is/are correct?… Explanation figure for the question: Let x be a real number between 0 and 1. Which of the following statements is/are correct?… Explanation figure for the question: Let x be a real number between 0 and 1. Which of the following statements is/are correct?… Explanation figure for the question: Let x be a real number between 0 and 1. Which of the following statements is/are correct?… Explanation figure for the question: Let x be a real number between 0 and 1. Which of the following statements is/are correct?… Explanation figure for the question: Let x be a real number between 0 and 1. Which of the following statements is/are correct?…