PSLE
A stationery kiosk is having a book sale. The 1st book is at 15% discount. The 2nd book is at 25% discount. The price of the 2nd book should be equal or lower than the price of the 1st book.

1. Betty's books were priced at $6 and $15. How much more did she pay for the 1st book than the 2nd book? 
2. Wesley paid a total of $53.85 for his two books. He paid $7.35 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% $15	100% $6
Discount	- 15%	- 25%
Sale price	85%	75%	?

(a)
Selling price of the 1st book
= 85% x 15
= ⁸⁵₁₀₀ x 15
= $12.75

Selling price of 2nd book
= 75% x 6
= ⁷⁵₁₀₀ x 6
= $4.50

Amount that Betty paid more for the 1st book than the 2nd book
= 12.75 - 4.50
= $8.25

	1st book	2nd book	Total amount
Original price	100%	100%
Discount	- 15%	- 25%
Sale price	85%	75%
Compare 1st book and 2nd book	1 u + $7.35	1 u	$53.85

(b)
Sale price of the 1st book = 1 u + 7.35
Sale price of the 2nd book = 1 u

Total amount that Wesley paid
= 1 u + 7.35 + 1 u
= 2 u + 7.35

2 u + 7.35 = 53.85
2 u = 53.85 - 7.35
2 u = 46.50

1 u = 46.50 ÷ 2 = 23.25

Sale price of the 1st book
= 1 u + 7.35
= $30.60

85% of the price = $30.60
100% of the price = ^30.60₈₅ x 100 = $36

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

Answer(s): (a) $8.25; (b) $36