PSLE
A stationery kiosk is having a book sale. The 1st book is at 10% discount. The 2nd book is at 40% discount. The price of the 2nd book should be equal or lower than the price of the 1st book.

1. Penelope's books were priced at $16 and $28. How much did she pay for them?
2. Flynn paid a total of $48.30 for his two books. He paid $11.10 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% $28	100% $16
Discount	- 10%	- 40%
Sale price	90%	60%	?

(a)
Selling price of the 1st book
= 90% x 28
= ⁹⁰₁₀₀ x 28
= $25.20

Selling price of 2nd book
= 60% x 16
= ⁶⁰₁₀₀ x 16
= $9.60

Total amount that Penelope paid
= 25.20 + 9.60
= $34.80

	1st book	2nd book	Total amount
Original price	100%	100%
Discount	- 10%	- 40%
Sale price	90%	60%
Compare 1st book and 2nd book	1 u + $11.10	1 u	$48.30

(b)
Sale price of the 1st book = 1 u + 11.10
Sale price of the 2nd book = 1 u

Total amount that Flynn paid
= 1 u + 11.10 + 1 u
= 2 u + 11.10

2 u + 11.10 = 48.30
2 u = 48.30 - 11.10
2 u = 37.20

1 u = 37.20 ÷ 2 = 18.60

Sale price of the 2nd book = $18.60

60% of the price = $18.60
100% of the price = ^18.60₆₀ x 100 = $31

Selling price of the 2nd book before discount = $31

Answer(s): (a) $34.80; (b) $31