Let the floor space of the largest building is x and the floor space of the smallest building is y.
Then, given that
[tex]x=3y\text{ (1)}[/tex][tex]x+y=2720\text{ (2)}[/tex]Substituting the value of x=3y from the equation (1) into the equation (2),
[tex]\begin{gathered} 3y+y=2720 \\ 4y=2720 \\ y=\frac{2720}{4} \\ y=680 \end{gathered}[/tex]Therefore,
[tex]\begin{gathered} x=3\times680 \\ x=2040 \end{gathered}[/tex]Hence, the floor space of the largest building is 2040 and the floor space of smaller building is 680 .