Problem: the length and breadth of the floor of the room are 20 feet and 10 feet respectively . square tiles of 2 feet length of different colours are to be laid on the floor . black tiles are laid in the first row on all sides . if white tiles are laid in the one - third of the remaining and blue tiles in the rest , how many blue tiles will be there ? 
Options: ['a ) 16', 'b ) 24', 'c ) 32', 'd ) 48', 'e ) none of these']
a