What should replace “?” in the following equation if “+” and “÷” are…
2026
What should replace “?” in the following equation if “+” and “÷” are interchanged and “−” and “×” are interchanged?
20 − 2 × 85 + 5 ÷ 15 = ?
Answer: D. 38 — ConceptWhen mathematical symbols are interchanged, first replace every occurrence of each symbol exactly as directed. Then evaluate the resulting expression…
- A.
30
- B.
28
- C.
35
- D.
38
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Show answer & explanation
Correct answer: D
Concept
When mathematical symbols are interchanged, first replace every occurrence of each symbol exactly as directed.
Then evaluate the resulting expression using the standard order of operations: multiplication and division before addition and subtraction, working left to right within the same priority.
Application
Apply the swaps: “−” becomes “×”, “×” becomes “−”, “+” becomes “÷”, and “÷” becomes “+”. The expression becomes 20 × 2 − 85 ÷ 5 + 15.
Evaluate multiplication and division: 20 × 2 = 40 and 85 ÷ 5 = 17.
Now evaluate from left to right: 40 − 17 + 15 = 23 + 15 = 38.
Cross-check
Substituting the changed symbols directly into the original expression gives the same sequence of operations, so the required value is 38.