Use an identity to simplify a ratio of sums of squares: Evaluate [(3.537 − 0.948)^2 + (3.537 + 0.948)^2] / [(3.537)^2 + (0.948)^2].

Aptitude Decimal Fraction Difficulty: Easy
Choose an option
  • A
    4
  • B
    2
  • C
    4.485
  • D
    2.589
  • E
    1

Answer

Correct Answer: 2

Explanation

Introduction / Context:This expression is designed for application of a standard algebraic identity. Recognizing structure avoids arduous arithmetic with decimals.

Given Data / Assumptions:

  • a = 3.537, b = 0.948.
  • Expression: [(a − b)^2 + (a + b)^2] / (a^2 + b^2).

Concept / Approach:Identity: (a − b)^2 + (a + b)^2 = 2a^2 + 2b^2 = 2(a^2 + b^2). Substitute this into the expression to simplify immediately.

Step-by-Step Solution:

Numerator = (a − b)^2 + (a + b)^2 = 2(a^2 + b^2)Denominator = (a^2 + b^2)Ratio = [2(a^2 + b^2)] / (a^2 + b^2) = 2

Verification / Alternative check:Compute a^2 + b^2 numerically if desired; the factor of 2 cancels regardless of specific values, confirming the identity-based simplification.

Why Other Options Are Wrong:4 and 4.485 overstate the result; 2.589 is arbitrary. 1 would occur if the numerator equaled the denominator, which is not the case here.

Common Pitfalls:Expanding each square separately and then adding may invite arithmetic errors. Spot the identity first to save time.

Final Answer:2

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