Mixed supply treated by the highest taxed component; tax classification and time of supply follow that dominant component. A mixed supply composed of multiple supplies is taxable as the single constituent supply that attracts the highest rate of tax, requiring use of that supply's tax rate and HSN classification for the entire package. Time-of-supply provisions follow the dominant component (service or goods). Optional items supplied independently are taxed separately. Administrative guidance and advance rulings apply this approach to bundled goods, entry fees including ancillary items, and combined lodging-and-food arrangements, which are treated as mixed supplies rather than composite supplies.