Dear Himanshu,
Hope you are doing well !!
The long term capital gain would be as below:
Sales consideration= Rs 1.30 Cr
Indexed cost of acquisition= Rs .45 Cr*280/184= Rs. .68 Cr i.e (Rs, 68,47,826)
LTCG= Rs. 1.30 Cr-.68 Cr= Rs. .61 Cr i.e. (Rs 61,52,174).
LTCG tax is 20.8% on Rs, 61,52,153/- = Rs 12,79,652/-
Per head - capital gain tax will be Rs. 6,39,836/-