Balance an equation by approximation: 1178.999 × 25.001 − 16.0011 × √(?) ≈ 29075. Find the best value of ?.

Difficulty: Medium

Correct Answer: 625

Explanation:

Introduction / Context:This equation has near-integer coefficients. We can approximate to integers to isolate √(?) and then square to obtain ? that balances the equation.Given Data / Assumptions:

  • LHS: 1178.999 × 25.001 − 16.0011 × √(?) ≈ 29075.
  • Approximate 1178.999 ≈ 1179, 25.001 ≈ 25, and 16.0011 ≈ 16.

Concept / Approach:Compute the first product approximately, then solve for √(?) using simple algebra. Finally, compute ? as the square of that value and match options.Step-by-Step Solution:

Approximate 1179 × 25 = 29475.Set 29475 − 16 × √(?) ≈ 29075.16 × √(?) ≈ 400 ⇒ √(?) ≈ 25.So ? ≈ 25^2 = 625.

Verification / Alternative check:Using the tiny decimal corrections (25.001, 16.0011) slightly shifts the balance but does not change the integer square root conclusion, confirming 625 is the best option.Why Other Options Are Wrong:

  • 25 or 15: These look like square roots, not the radicand.
  • 575: Not a perfect square and would not give a neat square root near 25.

Common Pitfalls:Choosing the square root value instead of ?. In equations of the form a − b*√(?) = c, always isolate √(?) first, then square to get the value of ? that the options refer to.Final Answer:

625

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