Difficulty: Medium
Correct Answer: 611/168
Explanation:
Introduction / Context:This calculation tests careful handling of mixed numbers, nested brackets, and fraction operations. Accuracy requires converting mixed numbers to improper fractions, respecting the order of operations, and simplifying step by step.
Given Data / Assumptions:
Concept / Approach:Work from the innermost parentheses outward. Convert mixed numbers early. Keep everything as exact fractions to avoid rounding errors. Finally, subtract from 5 as an improper fraction with a common denominator.
Step-by-Step Solution:
Innermost: (1/2 + 1/6 - 1/7) = 1/2 + 1/6 = 2/3; 2/3 - 1/7 = 14/21 - 3/21 = 11/21Now: 2 1/2 - (result) = 5/2 - 11/21 = (105 - 22)/42 = 83/42Add 3/4: 3/4 + 83/42 = (63 + 166)/84 = 229/84Divide by 2: (229/84)/2 = 229/168Finally: 5 - 229/168 = (840 - 229)/168 = 611/168Verification / Alternative check:
Approximate decimals: 611/168 ≈ 3.6369; evaluating the original numerically also gives ≈ 3.6369, confirming.Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:
611/168
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