A furniture store was having National Day discount of 20% off its usual price. The GST is at 8%. Penelope used her credit card to purchase a kitchen table and Zane used cash to pay for a similar kitchen table.

1. How much did Penelope pay in the end after GST? Round off your answer to the nearest cent.
2. How much did Zane pay in the end after GST? Round off your answer to the nearest ten cent.

New kitchen table Usual Price: $580

Further Discount: Pay by credit card: 5% off discounted price before GST! Pay by cash: $30 off discounted price before GST!

	Credit Card	Cash
Usual Price	$580	$580
Less 20% discount	- $116.00	- $116.00
Price after 20% discount	$464.00	$464.00
Less further discount	- $23.20	- $30
Price after further discount	$440.80	$434.00
Price after GST of 8%	$476.06	$468.70

(a)
New selling price after 20% discount
= 100% - 20%
= 80%

Price of the kitchen table after National Day discount
= 80% x 580
= ⁹⁵₁₀₀ x 580
= $464.00

New selling price after 5% further discount
= 100% - 5%
= 95%

Price of the kitchen table after credit card discount
= 95% x 464.00
= ⁹⁵₁₀₀ x 464.00
= $440.80

Price to pay after including GST
= 100% + 8%
= 108%

Price of the kitchen table after GST
= 108% x 440.80 
= ¹⁰⁸₁₀₀ x 440.80 
≈ $476.06 (Round off to nearest cent)

(b)
Price of the kitchen table after cash discount
= 464.00 - 30
= $434.00

Price of the kitchen table after GST
= 108% x 434.00 
= ¹⁰⁸₁₀₀ x 434.00 
≈ $468.70 (Round off to nearest ten cent)

Answer(s): (a) $476.06; (b) $468.70