PSLE
A stationery shop is having a book sale. The 1st book is at 5% discount. The 2nd book is at 15% discount. The price of the 2nd book should be equal or lower than the price of the 1st book.

1. Ivory's books were priced at $34 and $35. How much less did she pay for the 2nd book than the 1st book? 
2. Carl paid a total of $49.65 for his two books. He paid $5.45 less for the 2nd book than for the 1st book. What was the price of the 1st book before discount? 

	1st book	2nd book	Total amount
Original price	100% $35	100% $34
Discount	- 5%	- 15%
Sale price	95%	85%	?

(a)
Selling price of the 1st book
= 95% x 35
= ⁹⁵₁₀₀ x 35
= $33.25

Selling price of 2nd book
= 85% x 34
= ⁸⁵₁₀₀ x 34
= $28.90

Amount that Ivory paid less for the 2nd book than the 1st book
= 33.25 - 28.90
= $4.35

	1st book	2nd book	Total amount
Original price	100%	100%
Discount	- 5%	- 15%
Sale price	95%	85%
Compare 1st book and 2nd book	1 u + $5.45	1 u	$49.65

(b)
Sale price of the 1st book = 1 u + 5.45
Sale price of the 2nd book = 1 u

Total amount that Carl paid
= 1 u + 5.45 + 1 u
= 2 u + 5.45

2 u + 5.45 = 49.65
2 u = 49.65 - 5.45
2 u = 44.20

1 u = 44.20 ÷ 2 = 22.10

Sale price of the 1st book
= 1 u + 5.45
= $27.55

95% of the price = $27.55
100% of the price = ^27.55₉₅ x 100 = $29

Selling price of the 1st book before discount = $29

Answer(s): (a) $4.35; (b) $29