Difficulty: Medium
Correct Answer: 23 + 17 x 73 = 388
Explanation:
Introduction / Context:This is a two-layer transformation puzzle. First interchange the operators “+” and “×”. Second, replace every digit 3 with 7 and every digit 7 with 3 anywhere they occur (on both sides). After applying both swaps, check which equality holds numerically.
Given Data / Assumptions:
Concept / Approach:Transform each option entirely (LHS and RHS), then evaluate the transformed LHS to see whether it equals the transformed RHS.
Step-by-Step Solution:
Consider Option D: 23 + 17 × 73 = 388.After operator swap → 23 × 17 + 73; after digit swap → 27 × 13 + 37.Compute: 27 × 13 = 351; 351 + 37 = 388.RHS “388” has no 3/7 digits, so remains 388. Equality holds → Option D is correct.Verification / Alternative check:Quick checks on other options show mismatches after the two-step swap (e.g., Option A transforms to 27 × 13 + 37 = 388 on LHS but compares with 1241, which does not match).
Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:23 + 17 x 73 = 388
Discussion & Comments