If ‘+’ means ‘÷’, ‘–’ means ‘×’, ‘x’ means ‘+’, ‘÷’ means ‘–’, what will come in place of the question mark (?) in the following equation?
81 ÷ 3 – 14 ÷ 7 × 6 + 6 – 5 = ?

Given: ‘+’ means ‘÷’, ‘–’ means ‘×’, ‘x’ means ‘+’, ‘÷’ means ‘–’
Logic: interchange mathematical operators and solve as per BODMAS rule.

$$\begin{array}{|c|c|} \hline \textbf{Operation preference wise} & \textbf{Symbol} \\\hline Brackets &[],{}, () \\ \hline Orders, of & (power), √ (root) , of \\ \hline Division& ÷ \\ \hline Multiplication & × \\ \hline Addition & + \\ \hline Subtraction & - \\\hline \end{array}$$​
Given:
81 ÷ 3 – 14 ÷ 7 × 6 + 6 – 5
After interchanging,
81 - 3 × 14 - 7 + 6 ÷ 6 × 5
=81 - 42 - 7 + 1 × 5
=81 - 42 - 7 + 5
=37
Thus, correct option (b).​​