PSLE
A stationery shop is having a book sale. The 1st book is at 25% discount. The 2nd book is at 35% discount. The price of the 2nd book should be equal or lower than the price of the 1st book.

1. Gwen's books were priced at $19 and $21. How much did she pay for them?
2. Ethan paid a total of $41.75 for his two books. He paid $9.25 less for the 2nd book than the 1st book. What was the price of the 2nd book before discount? 

	1st book	2nd book	Total amount
Original price	100% $21	100% $19
Discount	- 25%	- 35%
Sale price	75%	65%	?

(a)
Selling price of the 1st book
= 75% x 21
= ⁷⁵₁₀₀ x 21
= $15.75

Selling price of 2nd book
= 65% x 19
= ⁶⁵₁₀₀ x 19
= $12.35

Total amount that Gwen paid
= 15.75 + 12.35
= $28.10

	1st book	2nd book	Total amount
Original price	100%	100%
Discount	- 25%	- 35%
Sale price	75%	65%
Compare 1st book and 2nd book	1 u + $9.25	1 u	$41.75

(b)
Sale price of the 1st book = 1 u + 9.25
Sale price of the 2nd book = 1 u

Total amount that Ethan paid
= 1 u + 9.25 + 1 u
= 2 u + 9.25

2 u + 9.25 = 41.75
2 u = 41.75 - 9.25
2 u = 32.50

1 u = 32.50 ÷ 2 = 16.25

Sale price of the 2nd book = $16.25

65% of the price = $16.25
100% of the price = ^16.25₆₅ x 100 = $25

Selling price of the 2nd book before discount = $25

Answer(s): (a) $28.10; (b) $25