PSLE
A store is having a book sale. The 1st book is at 20% discount. The 2nd book is at 25% discount. The price of the 2nd book should be equal or lower than the price of the 1st book.

1. Jean's books were priced at $11 and $14. How much did she pay for them?
2. Bobby paid a total of $31.85 for his two books. He paid $3.35 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% $11
Discount	- 20%	- 25%
Sale price	80%	75%	?

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

Selling price of 2nd book
= 75% x 11
= ⁷⁵₁₀₀ x 11
= $8.25

Total amount that Jean paid
= 11.20 + 8.25
= $19.45

	1st book	2nd book	Total amount
Original price	100%	100%
Discount	- 20%	- 25%
Sale price	80%	75%
Compare 1st book and 2nd book	1 u + $3.35	1 u	$31.85

(b)
Sale price of the 1st book = 1 u + 3.35
Sale price of the 2nd book = 1 u

Total amount that Bobby paid
= 1 u + 3.35 + 1 u
= 2 u + 3.35

2 u + 3.35 = 31.85
2 u = 31.85 - 3.35
2 u = 28.50

1 u = 28.50 ÷ 2 = 14.25

Sale price of the 2nd book = $14.25

75% of the price = $14.25
100% of the price = ^14.25₇₅ x 100 = $19

Selling price of the 2nd book before discount = $19

Answer(s): (a) $19.45; (b) $19