query on capital gain

1.Cost  of acquisition would be fair market value as on 01.04.1981

Capital Gain calculated as under

Sale consideration                         xxxx

Less cost of acquisition (1/2)       xxxx

Capital Gain                                      xxx

i think it also include cost of improvement.

It looks like it is jopint development agreement. In that case there will be two components:

One: This will be the sale of land comprised in the portion of construction that the builder(D) retains. In case we assume that the total land was 1000 sft total construction was 5000 sft and the area that A and B got was 1500 sft. In that case the land sold will be 1000/5000X3500 i.e 700 sft. You need to calculate the long term capital gains tax accordingly.

Two: The sale of apartment will be taxed again