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. Penelope's books were priced at $19 and $34. How much did she pay for them?
2. Sean paid a total of $51.05 for his two books. He paid $11.85 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% $34	100% $19
Discount	- 15%	- 30%
Sale price	85%	70%	?

(a)
Selling price of the 1st book
= 85% x 34
= ⁸⁵₁₀₀ x 34
= $28.90

Selling price of 2nd book
= 70% x 19
= ⁷⁰₁₀₀ x 19
= $13.30

Total amount that Penelope paid
= 28.90 + 13.30
= $42.20

	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 + $11.85	1 u	$51.05

(b)
Sale price of the 1st book = 1 u + 11.85
Sale price of the 2nd book = 1 u

Total amount that Sean paid
= 1 u + 11.85 + 1 u
= 2 u + 11.85

2 u + 11.85 = 51.05
2 u = 51.05 - 11.85
2 u = 39.20

1 u = 39.20 ÷ 2 = 19.60

Sale price of the 2nd book = $19.60

70% of the price = $19.60
100% of the price = ^19.60₇₀ x 100 = $28

Selling price of the 2nd book before discount = $28

Answer(s): (a) $42.20; (b) $28