Operator re-mapping evaluation: 'P' → '+'; 'Q' → '×'; 'R' → '÷'; 'S' → '−'. Evaluate using standard precedence (×, ÷ before +, −), left-to-right within the same tier: 44 Q 9 R 12 S 6 Q 4 P 16

Difficulty: Easy

Correct Answer: 25

Explanation:


Introduction / Context:
This coded-operations question tests translation of symbols into real operators and careful use of arithmetic precedence. Once each letter is decoded, we must evaluate the expression strictly with × and ÷ before + and −, and with left-to-right tie-breaking inside the same precedence tier.


Given Data / Assumptions:

  • P means +
  • Q means ×
  • R means ÷
  • S means −
  • Expression: 44 Q 9 R 12 S 6 Q 4 P 16
  • Use standard precedence and left-to-right evaluation for × and ÷.


Concept / Approach:
Translate first; then evaluate with precedence. A common mistake is to execute + or − too early or to ignore that × and ÷ are left-associative (performed from left to right when chained).


Step-by-Step Solution:
1) Decode → 44 × 9 ÷ 12 − 6 × 4 + 16 2) ×/÷ left→right: 44 × 9 = 396 3) 396 ÷ 12 = 33 4) Remaining ×: 6 × 4 = 24 5) Now +/− left→right: 33 − 24 = 9 6) 9 + 16 = 25


Verification / Alternative check:
Parenthesize by precedence: ((44 × 9) ÷ 12) − (6 × 4) + 16 = (396 ÷ 12) − 24 + 16 = 33 − 24 + 16 = 25.


Why Other Options Are Wrong:
36, 112, and 124 arise if precedence is ignored (doing +/− before ×/÷) or if × and ÷ are not processed left-to-right, which changes intermediate values and the final result.


Common Pitfalls:
Mixing up the code map (e.g., treating Q as +), performing +/− too soon, or reversing left-to-right order among ×/÷. Each leads to incorrect totals despite correct arithmetic steps elsewhere.


Final Answer:
25

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