PSLE
A stationery kiosk is having a book sale. The 1st book is at 15% discount. The 2nd book is at 35% discount. The price of the 2nd book should be equal or lower than the price of the 1st book.

1. Rachel's books were priced at $12 and $15. How much more did she pay for the 1st book than the 2nd book? 
2. Paul paid a total of $35.30 for his two books. He paid $10.60 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% $12
Discount	- 15%	- 35%
Sale price	85%	65%	?

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

Selling price of 2nd book
= 65% x 12
= ⁶⁵₁₀₀ x 12
= $7.80

Amount that Rachel paid more for the 1st book than the 2nd book
= 12.75 - 7.80
= $4.95

	1st book	2nd book	Total amount
Original price	100%	100%
Discount	- 15%	- 35%
Sale price	85%	65%
Compare 1st book and 2nd book	1 u + $10.60	1 u	$35.30

(b)
Sale price of the 1st book = 1 u + 10.60
Sale price of the 2nd book = 1 u

Total amount that Paul paid
= 1 u + 10.60 + 1 u
= 2 u + 10.60

2 u + 10.60 = 35.30
2 u = 35.30 - 10.60
2 u = 24.70

1 u = 24.70 ÷ 2 = 12.35

Sale price of the 1st book
= 1 u + 10.60
= $22.95

85% of the price = $22.95
100% of the price = ^22.95₈₅ x 100 = $27

Selling price of the 1st book before discount = $27

Answer(s): (a) $4.95; (b) $27