we know that
One of the couches takes up \(4/9\) of the wall and the other takes up \(1/5\) of the wall
so
To find out how much of the wall is covered by couches, add the two amounts
\(\frac{4}{9} +\frac{1}{5} =\frac{(5*4+9*1)}{9*5}=\frac{29}{45}\)
therefore
the answer is
\(\frac{29}{45}\) of the wall is covered by couches