3 100 000 USD are important for finishing the house, if we calculate only flats, not concerning commercial areas ,which should be sold minimum 6000 sq.m of dwelling spaces ( 6000 x 500 $ = 3000 000 $ ) which approximately comprises 60-90 flats, according to the area of each.

If we also mean the commercial area, then the commercial area should be sold fully 1100 sq.m and the dwelling space 3320 sq.m, this gives us the sum of the money for finishing the house 1100 * $1309 (average) + 3320 * $500 = $3 100 000

Also should be considered that The project includes two identical blocs, to finish one of them we need to invest around 1.5 - 1.5 million US dollars, so to finish one of them we need to sell around 30-40 flats (in each)