A furniture store was having Mother's Day discount of 10% off its usual price. The GST is at 6%. Zoe used her credit card to purchase a book shelf and George used cash to pay for a similar book shelf.

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

New book shelf Usual Price: $560

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

	Credit Card	Cash
Usual Price	$560	$560
Less 10% discount	- $56.00	- $56.00
Price after 10% discount	$504.00	$504.00
Less further discount	- $25.20	- $5
Price after further discount	$478.80	$499.00
Price after GST of 6%	$507.53	$528.90

(a)
New selling price after 10% discount
= 100% - 10%
= 90%

Price of the book shelf after Mother's Day discount
= 90% x 560
= ⁹⁵₁₀₀ x 560
= $504.00

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

Price of the book shelf after credit card discount
= 95% x 504.00
= ⁹⁵₁₀₀ x 504.00
= $478.80

Price to pay after including GST
= 100% + 6%
= 106%

Price of the book shelf after GST
= 106% x 478.80 
= ¹⁰⁶₁₀₀ x 478.80 
≈ $507.53 (Round off to nearest cent)

(b)
Price of the book shelf after cash discount
= 504.00 - 5
= $499.00

Price of the book shelf after GST
= 106% x 499.00 
= ¹⁰⁶₁₀₀ x 499.00 
≈ $528.90 (Round off to nearest ten cent)

Answer(s): (a) $507.53; (b) $528.90