PSLE A book shop is having a book sale.
The 1st book is at 10% discount.
The 2nd book is at 40% discount.
The price of the 2nd book should be equal or lower than the price of the 1st book.
Gwen and Ken each bought two books at the sale.
- Gwen's books were priced at $18 and $23. How much less did she pay for the 2nd book than the 1st book?
- Ken paid a total of $49.80 for his two books. He paid $11.40 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% $23 |
100% $18 |
|
Discount |
- 10% |
- 40% |
|
Sale price |
90% |
60% |
? |
(a)
Selling price of the 1st book
= 90% x 23
=
90100 x 23
= $20.70
Selling price of 2nd book
= 60% x 18
=
60100 x 18
= $10.80
Amount that Gwen paid less for the 2nd book than the 1st book
= 20.70 - 10.80
= $9.90
|
1st book |
2nd book |
Total amount |
Original price |
100% |
100% |
|
Discount |
- 10% |
- 40% |
|
Sale price |
90%
|
60%
|
|
Compare 1st book and 2nd book |
1 u + $11.40 |
1 u |
$49.80 |
(b)
Sale price of the 1st book = 1 u + 11.40
Sale price of the 2nd book = 1 u
Total amount that Ken paid
= 1 u + 11.40 + 1 u
= 2 u + 11.40
2 u + 11.40 = 49.80
2 u = 49.80 - 11.40
2 u = 38.40
1 u = 38.40 ÷ 2 = 19.20
Sale price of the 1st book
= 1 u + 11.40
= $30.60
90% of the price = $30.60
100% of the price =
30.6090 x 100 = $34
Selling price of the 1st book before discount = $34
Answer(s): (a) $9.90; (b) $34