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CSAT 2025 paper

UPSC CSE CSAT 2025 · Question 79 · Number system

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

CSAT 2025 · Q79

Number system Easy

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

  1. I.x² > x³.
  2. II.x > √x.

Select the correct answer using the code given below:

Answer & explanation

Answer: (a) I only

For a number between 0 and 1, higher powers get smaller and square roots get larger. So x² > x³ is true, but x > √x is false.

  1. Take x = 0.25 as a test value.
  2. I: x² = 0.0625 and x³ = 0.015625, so x² > x³. In general x² − x³ = x²(1 − x) > 0 for 0 < x < 1. True.
  3. II: √0.25 = 0.5, which is larger than 0.25, so x > √x is false. For 0 < x < 1, √x is always larger than x.
  4. Only statement I is correct.
  • ✓ I x² − x³ = x²(1 − x) is positive when 0 < x < 1, so x² > x³.
  • ✗ II For a fraction between 0 and 1 the square root is larger: √0.25 = 0.5 > 0.25.

Remember · Between 0 and 1: x³ < x² < x < √x. Test with x = 0.25 to confirm quickly.

Question and answer: UPSC's official GS Paper II (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·

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