Compute Service Tax payable

M/S WK, a Works Contractor has executed a works contract. The details are given
below :
Particulars
Gross amount charged for the works contract –  8,00,000
Value of goods transferred during execution of works contract – 3,00,000
VAT on above goods – 40,000
Compute the service tax payable, if any
(i) Assuming that he has not opted for the composition scheme.
(ii) Assuming that he has opted for the composition scheme.