If '+' means '÷', '–' means '+', '×' means '–', '÷' means '×', then what will come in place of the question mark (?) in the following equation?
320 + 64 – 18 ÷ 2 × 28 = ?

Correct option is D

Sol.
Given: 320 + 64 – 18 ÷ 2 × 28
As per the question-

Interchange the sign and we get following equation-
320 ÷ 64 + 18 × 2 - 28
Following the BODMAS rule (Bracket, Orders (i.e. powers and square roots, etc.), Division and Multiplication, Addition and Subtraction):
1. Division (÷): 5 + 18 × 2 – 28
2. Multiplication (×): 5 + 36 – 28
3. Addition (+): 41 – 28
4. Subtraction (-): 13
Correct answer is (d) 13.