S. 54: Capital gains-Profit on sale of property used for residence-Co-owners-New residential property jointly purchased by assessee and his wife-Actual contribution towards the purchase of the new house is a relevant factor while determining the eligible exemption-AO is directed to verify the proportion of investment made by the assessee and allow the exemption accordingly-Cost of improvement-The assessee has provided the best available documentary evidence in the form of contractor bills and work details, the claim for indexed cost of improvement is allowed to the assesse. [S. 45, 48]