What will replace ‘?’ in the following equation if ‘+’ and ‘×’ are…
2026
What will replace ‘?’ in the following equation if ‘+’ and ‘×’ are interchanged, and ‘−’ and ‘÷’ are interchanged?
18 − 2 ÷ 3 + 5 × 16 = ?
Answer: D. 10 — ConceptWhen mathematical symbols are interchanged, first rewrite every symbol according to the stated mapping. Then apply the standard order of operations:…
- A.
20
- B.
5
- C.
15
- D.
10
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Correct answer: D
Concept
When mathematical symbols are interchanged, first rewrite every symbol according to the stated mapping. Then apply the standard order of operations: division and multiplication before addition and subtraction, evaluating operations of equal priority from left to right.
Application
Replace each ‘−’ with ‘÷’, each ‘÷’ with ‘−’, each ‘+’ with ‘×’, and each ‘×’ with ‘+’.
The expression becomes 18 ÷ 2 − 3 × 5 + 16.
Evaluate division and multiplication first: 18 ÷ 2 = 9 and 3 × 5 = 15.
Substitute these values: 9 − 15 + 16 = −6 + 16 = 10.
Cross-check
Reading the rewritten expression from left to right after the priority operations gives 9 − 15 + 16, and direct addition of the signed terms again gives 10.
Therefore, the required value is 10.