PSLE
A stationery kiosk is having a book sale. The 1st book is at 15% 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.

1. Jane's books were priced at $19 and $31. How much did she pay for them?
2. Billy paid a total of $43.90 for his two books. He paid $8.80 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% $19
Discount	- 15%	- 35%
Sale price	85%	65%	?

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

Selling price of 2nd book
= 65% x 19
= ⁶⁵₁₀₀ x 19
= $12.35

Total amount that Jane paid
= 26.35 + 12.35
= $38.70

	1st book	2nd book	Total amount
Original price	100%	100%
Discount	- 15%	- 35%
Sale price	85%	65%
Compare 1st book and 2nd book	1 u + $8.80	1 u	$43.90

(b)
Sale price of the 1st book = 1 u + 8.80
Sale price of the 2nd book = 1 u

Total amount that Billy paid
= 1 u + 8.80 + 1 u
= 2 u + 8.80

2 u + 8.80 = 43.90
2 u = 43.90 - 8.80
2 u = 35.10

1 u = 35.10 ÷ 2 = 17.55

Sale price of the 2nd book = $17.55

65% of the price = $17.55
100% of the price = ^17.55₆₅ x 100 = $27

Selling price of the 2nd book before discount = $27

Answer(s): (a) $38.70; (b) $27