If + = ×, − = ÷, × = −, ÷ = +; 6 + 2 − 4 × 2 ÷ 1 = ?

Correct — A.
Rule: replace every sign first, then apply BODMAS.

Given: + means ×, − means ÷, × means −, ÷ means +.
6 + 2 − 4 × 2 ÷ 1 becomes 6 × 2 ÷ 4 − 2 + 1.

Multiply: 6 × 2 = 12
Divide: 12 ÷ 4 = 3
Subtract, then add: 3 − 2 + 1 = 2 → option (a).

Why the others are wrong

• (b)
  4 — 4 comes from reading the code as two swaps, + with × and − with ÷. That turns × into + and gives 6 × 2 ÷ 4 + 2 − 1 = 4, but here × means −.
• (c)
  10 — 10 cannot come from the converted expression. Its × and ÷ part gives 3, and the remaining − 2 + 1 changes that by −1, leaving 2.
• (d)
  8 — 8 would need the value to grow after 6 × 2 ÷ 4 = 3. The steps left, − 2 and + 1, shrink it to 2 instead.

A symbol-substitution question redefines the four signs. Convert the whole expression first, and only then calculate with ordinary BODMAS: × and ÷ left to right, then + and − left to right.

Read the direction with care: + = × means the + printed in the question stands for ×. Here the four meanings form one cycle, + → × → − → ÷ → +, not two swapped pairs, so × does not turn back into +.

Key facts

• Converted expression: 6 × 2 ÷ 4 − 2 + 1 = 2.
• BODMAS takes × and ÷ left to right before + and − left to right.
• The four meanings here form one cycle, + → × → − → ÷ → +, not two pairs.

Common traps

• Treating the code as two swaps so that × becomes +, which gives 4
• Adding before subtracting, 3 − (2 + 1) = 0, when + and − go left to right

No directly related past PYQ was found.