(1)Where the total income of an assessee includes any income arising from the transfer of a long-term capital asset which is chargeable under the head "Capital gains", the tax payable by the assessee on the total income, subject to sub-sections (2), (3) and (4), shall be the aggregate of—(a)income-tax payable on the total income as reduced by such long-term capital gains, had the total income, as so reduced, been his total income; and(b)income-tax calculated on such long-term capital gains at the rate of 12.5%.