PSLE
A bookstore is having a book sale. The 1st book is at 10% 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. Yen's books were priced at $16 and $26. How much less did she pay for the 2nd book than the 1st book? 
2. Luis paid a total of $50.60 for his two books. He paid $14.20 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% $26	100% $16
Discount	- 10%	- 30%
Sale price	90%	70%	?

(a)
Selling price of the 1st book
= 90% x 26
= ⁹⁰₁₀₀ x 26
= $23.40

Selling price of 2nd book
= 70% x 16
= ⁷⁰₁₀₀ x 16
= $11.20

Amount that Yen paid less for the 2nd book than the 1st book
= 23.40 - 11.20
= $12.20

	1st book	2nd book	Total amount
Original price	100%	100%
Discount	- 10%	- 30%
Sale price	90%	70%
Compare 1st book and 2nd book	1 u + $14.20	1 u	$50.60

(b)
Sale price of the 1st book = 1 u + 14.20
Sale price of the 2nd book = 1 u

Total amount that Luis paid
= 1 u + 14.20 + 1 u
= 2 u + 14.20

2 u + 14.20 = 50.60
2 u = 50.60 - 14.20
2 u = 36.40

1 u = 36.40 ÷ 2 = 18.20

Sale price of the 1st book
= 1 u + 14.20
= $32.40

90% of the price = $32.40
100% of the price = ^32.40₉₀ x 100 = $36

Selling price of the 1st book before discount = $36

Answer(s): (a) $12.20; (b) $36