Difficulty: Easy
Correct Answer: 850
Explanation:
Introduction / Context:
The expression is dominated by the product 6.39*128.948. The division term is small (≈0.43), and the constant is modest. A careful product estimate plus the small add-ons will point clearly to the nearest option.
Given Data / Assumptions:
Concept / Approach:
Approximate 128.948 ≈ 129; 6.39*129 = 6.39*(130 − 1) = 830.7 − 6.39 = 824.31. Add the small division (~0.43) and the constant 25.056 to reach the final estimate near 850.
Step-by-Step Solution:
Verification / Alternative check:
Exact computation gives about 849.46, still nearest to 850 compared with 800, 900, or 950.
Why Other Options Are Wrong:
800 is too low by ~49; 900 and 950 are too high. 850 is closest.
Common Pitfalls:
Ignoring the constant 25.056 or over-rounding 128.948 to 130 without subtracting the 6.39 correction.
Final Answer:
850
Discussion & Comments