PSLE
A store is having a book sale. The 1st book is at 5% 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. Olivia's books were priced at $36 and $36. How much more did she pay for the 1st book than the 2nd book? 
2. Lee paid a total of $40.60 for his two books. He paid $10.70 less for the 2nd book than for the 1st book. What was the price of the 1st book before discount? 

	1st book	2nd book	Total amount
Original price	100% $36	100% $36
Discount	- 5%	- 35%
Sale price	95%	65%	?

(a)
Selling price of the 1st book
= 95% x 36
= ⁹⁵₁₀₀ x 36
= $34.20

Selling price of 2nd book
= 65% x 36
= ⁶⁵₁₀₀ x 36
= $23.40

Amount that Olivia paid more for the 1st book than the 2nd book
= 34.20 - 23.40
= $10.80

	1st book	2nd book	Total amount
Original price	100%	100%
Discount	- 5%	- 35%
Sale price	95%	65%
Compare 1st book and 2nd book	1 u + $10.70	1 u	$40.60

(b)
Sale price of the 1st book = 1 u + 10.70
Sale price of the 2nd book = 1 u

Total amount that Lee paid
= 1 u + 10.70 + 1 u
= 2 u + 10.70

2 u + 10.70 = 40.60
2 u = 40.60 - 10.70
2 u = 29.90

1 u = 29.90 ÷ 2 = 14.95

Sale price of the 1st book
= 1 u + 10.70
= $25.65

95% of the price = $25.65
100% of the price = ^25.65₉₅ x 100 = $27

Selling price of the 1st book before discount = $27

Answer(s): (a) $10.80; (b) $27