The invoice value of 48 bottles is 48 × 90 cents = $43.20
Tare and leakage are 7% of $43.20 = $ 3.024
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Value on which duty is paid $40.176
Ad valorem duty is 25% of $40.176 = $10.044
Specific duty is 48 × 20 cents = 9.60
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Total duty $19.644