PSLE
A stationery kiosk is having a book sale. The 1st book is at 20% discount. The 2nd book is at 30% discount. The price of the 2nd book should be equal or lower than the price of the 1st book.

1. Sarah's books were priced at $12 and $14. How much did she pay for them?
2. Albert paid a total of $49.10 for his two books. He paid $8.50 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% $14	100% $12
Discount	- 20%	- 30%
Sale price	80%	70%	?

(a)
Selling price of the 1st book
= 80% x 14
= ⁸⁰₁₀₀ x 14
= $11.20

Selling price of 2nd book
= 70% x 12
= ⁷⁰₁₀₀ x 12
= $8.40

Total amount that Sarah paid
= 11.20 + 8.40
= $19.60

	1st book	2nd book	Total amount
Original price	100%	100%
Discount	- 20%	- 30%
Sale price	80%	70%
Compare 1st book and 2nd book	1 u + $8.50	1 u	$49.10

(b)
Sale price of the 1st book = 1 u + 8.50
Sale price of the 2nd book = 1 u

Total amount that Albert paid
= 1 u + 8.50 + 1 u
= 2 u + 8.50

2 u + 8.50 = 49.10
2 u = 49.10 - 8.50
2 u = 40.60

1 u = 40.60 ÷ 2 = 20.30

Sale price of the 2nd book = $20.30

70% of the price = $20.30
100% of the price = ^20.30₇₀ x 100 = $29

Selling price of the 2nd book before discount = $29

Answer(s): (a) $19.60; (b) $29