PSLE
A store is having a book sale.

The 1st book is at 20% 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.

Min and Flynn each bought two books at the sale.

1. Min's books were priced at $16 and $24. How much more did she pay for the 1st book than the 2nd book? 
2. Flynn paid a total of $47.65 for his two books. He paid $9.95 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% $24	100% $16
Discount	- 20%	- 35%
Sale price	80%	65%	?

(a)
Selling price of the 1st book
= 80% x 24
= ⁸⁰₁₀₀ x 24
= $19.20

Selling price of 2nd book
= 65% x 16
= ⁶⁵₁₀₀ x 16
= $10.40

Amount that Min paid more for the 1st book than the 2nd book
= 19.20 - 10.40
= $8.80

	1st book	2nd book	Total amount
Original price	100%	100%
Discount	- 20%	- 35%
Sale price	80%	65%
Compare 1st book and 2nd book	1 u + $9.95	1 u	$47.65

(b)
Sale price of the 1st book = 1 u + 9.95
Sale price of the 2nd book = 1 u

Total amount that Flynn paid
= 1 u + 9.95 + 1 u
= 2 u + 9.95

2 u + 9.95 = 47.65
2 u = 47.65 - 9.95
2 u = 37.70

1 u = 37.70 ÷ 2 = 18.85

Sale price of the 1st book
= 1 u + 9.95
= $28.80

80% of the price = $28.80
100% of the price = ^28.80₈₀ x 100 = $36

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

Answer(s): (a) $8.80; (b) $36