Decode the rule — If 73 + 82 = 14 and 91 + 21 = 11, then compute 86 + 24

Introduction / Context:These are not ordinary additions; a hidden rule maps two two-digit numbers to a small result. We must infer and apply the rule.

Given Data / Assumptions:

• 73 + 82 = 14
• 91 + 21 = 11

Concept / Approach:A compact rule fitting both examples is: (sum of tens digits) − (difference of units digits) = result. Formally, (a + c) − |b − d| for numbers ab and cd.

Step-by-Step Solution:

Verification / Alternative check:Other simple hypotheses (sum of all digits, etc.) fail on both examples, confirming this rule.

Why Other Options Are Wrong:

• 9/6/62 do not follow the established mapping.

Common Pitfalls:

• Assuming ordinary addition.

Final Answer:8