PSLE
A shop is having a book sale. The 1st book is at 15% discount. The 2nd book is at 20% discount. The price of the 2nd book should be equal or lower than the price of the 1st book.

1. Julie's books were priced at $31 and $31. How much did she pay for them?
2. Flynn paid a total of $59.55 for his two books. He paid $6.75 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% $31	100% $31
Discount	- 15%	- 20%
Sale price	85%	80%	?

(a)
Selling price of the 1st book
= 85% x 31
= ⁸⁵₁₀₀ x 31
= $26.35

Selling price of 2nd book
= 80% x 31
= ⁸⁰₁₀₀ x 31
= $24.80

Total amount that Julie paid
= 26.35 + 24.80
= $51.15

	1st book	2nd book	Total amount
Original price	100%	100%
Discount	- 15%	- 20%
Sale price	85%	80%
Compare 1st book and 2nd book	1 u + $6.75	1 u	$59.55

(b)
Sale price of the 1st book = 1 u + 6.75
Sale price of the 2nd book = 1 u

Total amount that Flynn paid
= 1 u + 6.75 + 1 u
= 2 u + 6.75

2 u + 6.75 = 59.55
2 u = 59.55 - 6.75
2 u = 52.80

1 u = 52.80 ÷ 2 = 26.40

Sale price of the 2nd book = $26.40

80% of the price = $26.40
100% of the price = ^26.40₈₀ x 100 = $33

Selling price of the 2nd book before discount = $33

Answer(s): (a) $51.15; (b) $33