If 'A' stands for '÷', 'B' stands for '×', 'C' stands for '+' and 'D' stands for '-', what will come in place of the question mark (?) in the following equation? 21 B 4 D 49 A 7 C 10 = ?

What will come in place of the question mark (?) in the following equation, if '+' and '-' are interchanged and '×' and '÷' are interchanged? 37 ÷ 5 - 91 + 16 × 4 = ?

If '+' and '-' are interchanged, and '×' and '÷' are interchanged, then what will come in place of the question mark (?) in the following equation? 26 ÷ 676 × 156 - 69 + 83 = ?