A furniture store was having Year End discount of 25% off its usual price. The GST is at 8%. Gwen used her credit card to purchase a sofa bed and Julian used cash to pay for a similar sofa bed.

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

New sofa bed Usual Price: $640

Further Discount: Pay by credit card: 10% off discounted price before GST! Pay by cash: $25 off discounted price before GST!

	Credit Card	Cash
Usual Price	$640	$640
Less 25% discount	- $160.00	- $160.00
Price after 25% discount	$480.00	$480.00
Less further discount	- $48.00	- $25
Price after further discount	$432.00	$455.00
Price after GST of 8%	$466.56	$491.40

(a)
New selling price after 25% discount
= 100% - 25%
= 75%

Price of the sofa bed after Year End discount
= 75% x 640
= ⁹⁰₁₀₀ x 640
= $480.00

New selling price after 10% further discount
= 100% - 10%
= 90%

Price of the sofa bed after credit card discount
= 90% x 480.00
= ⁹⁰₁₀₀ x 480.00
= $432.00

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

Price of the sofa bed after GST
= 108% x 432.00 
= ¹⁰⁸₁₀₀ x 432.00 
≈ $466.56 (Round off to nearest cent)

(b)
Price of the sofa bed after cash discount
= 480.00 - 25
= $455.00

Price of the sofa bed after GST
= 108% x 455.00 
= ¹⁰⁸₁₀₀ x 455.00 
≈ $491.40 (Round off to nearest ten cent)

Answer(s): (a) $466.56; (b) $491.40