Two-decimal percent of a decimal: Estimate 12.49% of 839.859 and select the nearest option.

Difficulty: Easy

Correct Answer: 105

Explanation:


Introduction / Context:
Percent of a decimal is handled the same as percent of an integer: multiply by the percent expressed as a decimal. Here 12.49% = 0.1249, and the base is ≈ 840, making the estimate straightforward and very close to a three-digit number slightly above 100.


Given Data / Assumptions:

  • Base = 839.859
  • Percent = 12.49% = 0.1249


Concept / Approach:
Compute 0.1249 * 839.859. For a quick estimate, use 0.125 * 840 = 105, then recognize that 0.1249 and 839.859 will land slightly under or around 105, making 105 the closest choice.


Step-by-Step Solution:

Approximation: 0.125 * 840 = 105Tighter calculation with 0.1249 * 839.859 ≈ 104.9Nearest option remains 105


Verification / Alternative check:
Even the exact product 104.9... is closer to 105 than to 100 or 95. Thus, 105 is the correct nearest option among the choices provided.


Why Other Options Are Wrong:

  • 95, 100: underestimate the computed value.
  • 115: overestimates by about 10.
  • 90: much too small.


Common Pitfalls:
Using 12.49 (not percent) directly as a factor, or erroneously rounding the base down to 800 which would bias the estimate too low.


Final Answer:
105

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