If '31 C 19 D 57 = 93' and '52 C 13 D 5 = 20', then '98 C 14 D 11 = ?'

If 'A' stands for '÷', 'B' stands for '×', 'C' stands for '+' and 'D' stands for '-', then what will come in place of the question mark (?) in the following equation? 13 B 2 C 6 D 8 A 4 = ?

Which two signs should be interchanged to make the given equation correct? 30 + 35 × 7 - 3 ÷ 10 = 5