If the first building was designed to have 4000 units, the second building, which had 2/5 times as many units as the first building, was to have 2/5*4000 = 1600 more units.
Together, the first and the second building had to have 1600+4000=<<1600+4000=5600>>5600.
The third building was to have 120/100*1600=<<120/100*1600=1920>>1920 units
Altogether, Daleyza won a project that required her to construct 5600+1920=<<5600+1920=7520>>7520 units.
#### 7520