The Central Goods and Services Act, 2017 (CGST Act)
Section 8 – Tax liability on composite and mixed supplies
The tax liability on a composite or a mixed supply shall be determined in the following manner namely:—
(a) a composite supply comprising two or more supplies one of which is a principal supply shall be treated as a supply of such principal supply and
(b) a mixed supply comprising two or more supplies shall be treated as a supply of that particular supply which attracts the highest rate of tax.