How many bricks will be required for a wall which is $8\;cm$ long $6\;cm$ high and $22.5\;cm$thick if each brick measures $25 \;cm \times 11.25\;cm \times 6\;cm$

Question

$\begin{array}{1 1} 640 \\ 6400 \\ 6500 \\ 6600 \end{array} $