PSLE
A shop is having a book sale. The 1st book is at 10% discount. The 2nd book is at 40% discount. The price of the 2nd book should be equal or lower than the price of the 1st book.

1. Opal's books were priced at $26 and $27. How much less did she pay for the 2nd book than the 1st book? 
2. Luis paid a total of $45.90 for his two books. He paid $13.50 more for the 1st book than for the 2nd book. What was the price of the 1st book before discount? 

	1st book	2nd book	Total amount
Original price	100% $27	100% $26
Discount	- 10%	- 40%
Sale price	90%	60%	?

(a)
Selling price of the 1st book
= 90% x 27
= ⁹⁰₁₀₀ x 27
= $24.30

Selling price of 2nd book
= 60% x 26
= ⁶⁰₁₀₀ x 26
= $15.60

Amount that Opal paid less for the 2nd book than the 1st book
= 24.30 - 15.60
= $8.70

	1st book	2nd book	Total amount
Original price	100%	100%
Discount	- 10%	- 40%
Sale price	90%	60%
Compare 1st book and 2nd book	1 u + $13.50	1 u	$45.90

(b)
Sale price of the 1st book = 1 u + 13.50
Sale price of the 2nd book = 1 u

Total amount that Luis paid
= 1 u + 13.50 + 1 u
= 2 u + 13.50

2 u + 13.50 = 45.90
2 u = 45.90 - 13.50
2 u = 32.40

1 u = 32.40 ÷ 2 = 16.20

Sale price of the 1st book
= 1 u + 13.50
= $29.70

90% of the price = $29.70
100% of the price = ^29.70₉₀ x 100 = $33

Selling price of the 1st book before discount = $33

Answer(s): (a) $8.70; (b) $33