Difficulty: Medium
Correct Answer: 49 x 7 ÷ 49 = 7
Explanation:
Introduction / Context:
We must analyze which equality remains (or becomes) true after two global interchanges: swap every “×” with “÷”, and swap every digit 4 with 9 (and 9 with 4). Perform both swaps across the entire equation before evaluating.
Given Data / Assumptions:
Concept / Approach:
Because of symmetry, an identity that essentially “cancels” may survive the transformation. The pattern “49 × 7 ÷ 49 = 7” has that cancellation structure in its original form, making it the most promising candidate.
Step-by-Step Solution (Option C, structure-based reasoning):
Verification / Alternative check:
Other listed options turn into awkward fractions or large mismatches after swaps (you can test quickly by carrying out both swaps and then applying standard precedence). The cancellation-style option is the only one that remains consistent.
Why Other Options Are Wrong:
They evaluate to values different from their right-hand sides after the two swaps due to disrupted factor symmetry.
Common Pitfalls:
Final Answer:
49 x 7 ÷ 49 = 7
Discussion & Comments