Use reasoning to lead to the answer of the following question:
Daleyza won a house construction project that involved the construction of three houses with several units. The first building was designed to have 4000 units, the second building 2/5 times as many units as the first building, and the third building was to have 20% more units than the second building. How many units were Daleyza contracted to build?

7520
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 = 5600.

The third building was to have 120 / 100 * 1600 = 1920 units.

Altogether, Daleyza won a project that required her to construct 5600 + 1920 = 7520 units.

.

So, the final answer is 7520