Select the number that will come in the place of the question mark(?), if ‘+’ and ‘ – ‘ are interchanged and ‘×’ and ‘÷’ are interchanged 93 – 7 ÷ 65 × 13 + 34 = ?

Correct — D.

Rule: rewrite the line with the swapped symbols first, then apply BODMAS to the new line. The swap changes symbols, never the order of operations.

93 – 7 ÷ 65 × 13 + 34 becomes 93 + 7 × 65 ÷ 13 – 34.

7 × 65 = 455
455 ÷ 13 = 35

93 + 35 = 128
128 – 34 = 94 → option (d)

Why the others are wrong

• (a)
  99 — 99 is unreachable. Tested across every arrangement of +, –, × and ÷ over 93, 7, 65, 13 and 34 under BODMAS, no arrangement evaluates to 99.
• (b)
  104 — 104 is reachable only as 93 – 7 + 65 – 13 – 34, which leaves the printed – alone while turning the printed + into –. No consistent reading of the two swaps produces that.
• (c)
  87 — 87 is unreachable for the same reason as 99: no arrangement of the four operators over these five numbers produces it under BODMAS.

Symbol-substitution items test one habit: finishing the substitution before starting the arithmetic.

Write the line out again in full with the new symbols. Every – becomes +, every + becomes –, every ÷ becomes × and every × becomes ÷, so the line reads 93 + 7 × 65 ÷ 13 – 34.

BODMAS then applies to the rewritten line exactly as it would to any other. Multiplication and division are settled first, taken left to right, and only then the addition and subtraction.

That is why 7 × 65 ÷ 13 collapses to 35 before anything is added to 93.

Key facts

• After the swap the expression reads 93 + 7 × 65 ÷ 13 – 34.
• 7 × 65 ÷ 13 = 35, taken left to right.
• 93 + 35 – 34 = 94.
• The swap replaces symbols only and leaves the order of operations untouched.

Common traps

• Swapping one pair and forgetting the other
• Working the rewritten line straight from left to right instead of by BODMAS
• Evaluating the original line and then adjusting the answer

No directly related past PYQ was found.