PSLE A stationery 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.
Olivia and Vincent each bought two books at the sale.
- Olivia's books were priced at $18 and $22. How much less did she pay for the 2nd book than the 1st book?
- Vincent paid a total of $28.30 for his two books. He paid $9.10 more for the 1st book than for the 2nd book. What was the price of the 1st book before discount?
|
1st book |
2nd book |
Total amount |
Original price
|
100% $22 |
100% $18 |
|
Discount |
- 15% |
- 20% |
|
Sale price |
85% |
80% |
? |
(a)
Selling price of the 1st book
= 85% x 22
=
85100 x 22
= $18.70
Selling price of 2nd book
= 80% x 18
=
80100 x 18
= $14.40
Amount that Olivia paid less for the 2nd book than the 1st book
= 18.70 - 14.40
= $4.30
|
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 + $9.10 |
1 u |
$28.30 |
(b)
Sale price of the 1st book = 1 u + 9.10
Sale price of the 2nd book = 1 u
Total amount that Vincent paid
= 1 u + 9.10 + 1 u
= 2 u + 9.10
2 u + 9.10 = 28.30
2 u = 28.30 - 9.10
2 u = 19.20
1 u = 19.20 ÷ 2 = 9.60
Sale price of the 1st book
= 1 u + 9.10
= $18.70
85% of the price = $18.70
100% of the price =
18.7085 x 100 = $22
Selling price of the 1st book before discount = $22
Answer(s): (a) $4.30; (b) $22