Respuesta :

$3.18 when the tax is applied to each bottle separately or at the end of the bill.

 
The bill before tax is
.. 3*$0.99 = $2.97

The tax is
.. 0.07*$2.97 = $0.2079 ≈ $0.21

The total bill, including tax is
.. $2.97 +0.21 = $3.18

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This is how every bill is computed wherever you may shop. It is a good idea to figure this out.