A New Tax System (Goods and Services Tax) Act 1999
If a supply (the actual supply ) is:
(a) partly a *taxable supply; and
(b) partly a supply that is *GST-free or *input taxed;
the value of the part of the actual supply that is a taxable supply is the proportion of the value of the actual supply that the taxable supply represents.
The value of the actual supply, for the purposes of subsection (1), is as follows:
*Price of the actual supply × 10
10 + Taxable proportion
is the proportion of the value of the actual supply that represents the value of the *taxable supply (expressed as a number between 0 and 1).