lf '+‘ means '–', ‘–‘ means ‘÷', ‘÷' means ‘×’ and '×' means ‘+'. what will come in place of the question mark (?)in the following equation?
21 + 48 – 8 × 6 ÷ 4 =?

​21 + 48 – 8 × 6 ÷ 4 =?
Concept used:

$$\begin{array}{|c|c|} \hline \textbf{Operation preference wise} & \textbf{Symbol} \\\hline Brackets &[],{}, () \\ \hline Orders, of & (power), √ (root) , of \\ \hline Division& ÷ \\ \hline Multiplication & × \\ \hline Addition & + \\ \hline Subtraction & - \\\hline \end{array}$$​​

​'+‘means '–', ‘–‘means ‘÷', ‘÷' means ‘×’ and '×' means ‘+'.
The modified equation becomes:

=21 - 48 ÷ 8 + 6 × 4 
=21- 6 +6 $$\times$$ 4

=21-6+24

=15+24

=39

Thus, correct option is (d)​