PSLE
A book shop is having a book sale. The 1st book is at 5% 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. Penelope's books were priced at $18 and $30. How much did she pay for them?
2. Reggie paid a total of $40.35 for his two books. He paid $10.95 more for the 1st book than the 2nd book. What was the price of the 2nd book before discount? 

	1st book	2nd book	Total amount
Original price	100% $30	100% $18
Discount	- 5%	- 30%
Sale price	95%	70%	?

(a)
Selling price of the 1st book
= 95% x 30
= ⁹⁵₁₀₀ x 30
= $28.50

Selling price of 2nd book
= 70% x 18
= ⁷⁰₁₀₀ x 18
= $12.60

Total amount that Penelope paid
= 28.50 + 12.60
= $41.10

	1st book	2nd book	Total amount
Original price	100%	100%
Discount	- 5%	- 30%
Sale price	95%	70%
Compare 1st book and 2nd book	1 u + $10.95	1 u	$40.35

(b)
Sale price of the 1st book = 1 u + 10.95
Sale price of the 2nd book = 1 u

Total amount that Reggie paid
= 1 u + 10.95 + 1 u
= 2 u + 10.95

2 u + 10.95 = 40.35
2 u = 40.35 - 10.95
2 u = 29.40

1 u = 29.40 ÷ 2 = 14.70

Sale price of the 2nd book = $14.70

70% of the price = $14.70
100% of the price = ^14.70₇₀ x 100 = $21

Selling price of the 2nd book before discount = $21

Answer(s): (a) $41.10; (b) $21