PSLE
A store is having a book sale. The 1st book is at 15% discount. The 2nd book is at 30% discount. The price of the 2nd book should be equal or lower than the price of the 1st book.

1. Pamela's books were priced at $38 and $39. How much less did she pay for the 2nd book than the 1st book? 
2. Zeph paid a total of $39.35 for his two books. He paid $9.95 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% $39	100% $38
Discount	- 15%	- 30%
Sale price	85%	70%	?

(a)
Selling price of the 1st book
= 85% x 39
= ⁸⁵₁₀₀ x 39
= $33.15

Selling price of 2nd book
= 70% x 38
= ⁷⁰₁₀₀ x 38
= $26.60

Amount that Pamela paid less for the 2nd book than the 1st book
= 33.15 - 26.60
= $6.55

	1st book	2nd book	Total amount
Original price	100%	100%
Discount	- 15%	- 30%
Sale price	85%	70%
Compare 1st book and 2nd book	1 u + $9.95	1 u	$39.35

(b)
Sale price of the 1st book = 1 u + 9.95
Sale price of the 2nd book = 1 u

Total amount that Zeph paid
= 1 u + 9.95 + 1 u
= 2 u + 9.95

2 u + 9.95 = 39.35
2 u = 39.35 - 9.95
2 u = 29.40

1 u = 29.40 ÷ 2 = 14.70

Sale price of the 1st book
= 1 u + 9.95
= $24.65

85% of the price = $24.65
100% of the price = ^24.65₈₅ x 100 = $29

Selling price of the 1st book before discount = $29

Answer(s): (a) $6.55; (b) $29