PSLE A stationery shop is having a book sale.
The 1st book is at 10% 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.
Jen and Luis each bought two books at the sale.
- Jen's books were priced at $11 and $21. How much did she pay for them?
- Luis paid a total of $30.20 for his two books. He paid $9.40 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% $21 |
100% $11 |
|
Discount |
- 10% |
- 20% |
|
Sale price |
90% |
80% |
? |
(a)
Selling price of the 1st book
= 90% x 21
=
90100 x 21
= $18.90
Selling price of 2nd book
= 80% x 11
=
80100 x 11
= $8.80
Total amount that Jen paid
= 18.90 + 8.80
= $27.70
|
1st book |
2nd book |
Total amount |
Original price |
100% |
100% |
|
Discount |
- 10% |
- 20% |
|
Sale price |
90%
|
80%
|
|
Compare 1st book and 2nd book |
1 u + $9.40 |
1 u |
$30.20 |
(b)
Sale price of the 1st book = 1 u + 9.40
Sale price of the 2nd book = 1 u
Total amount that Luis paid
= 1 u + 9.40 + 1 u
= 2 u + 9.40
2 u + 9.40 = 30.20
2 u = 30.20 - 9.40
2 u = 20.80
1 u = 20.80 ÷ 2 = 10.40
Sale price of the 2nd book = $10.40
80% of the price = $10.40
100% of the price =
10.4080 x 100 = $13
Selling price of the 2nd book before discount = $13
Answer(s): (a) $27.70; (b) $13