PSLE
A bookstore 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. Linda's books were priced at $3 and $18. How much did she pay for them?
2. Nick paid a total of $28.25 for his two books. He paid $7.45 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% $18	100% $3
Discount	- 15%	- 35%
Sale price	85%	65%	?

(a)
Selling price of the 1st book
= 85% x 18
= ⁸⁵₁₀₀ x 18
= $15.30

Selling price of 2nd book
= 65% x 3
= ⁶⁵₁₀₀ x 3
= $1.95

Total amount that Linda paid
= 15.30 + 1.95
= $17.25

	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 + $7.45	1 u	$28.25

(b)
Sale price of the 1st book = 1 u + 7.45
Sale price of the 2nd book = 1 u

Total amount that Nick paid
= 1 u + 7.45 + 1 u
= 2 u + 7.45

2 u + 7.45 = 28.25
2 u = 28.25 - 7.45
2 u = 20.80

1 u = 20.80 ÷ 2 = 10.40

Sale price of the 2nd book = $10.40

65% of the price = $10.40
100% of the price = ^10.40₆₅ x 100 = $16

Selling price of the 2nd book before discount = $16

Answer(s): (a) $17.25; (b) $16