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.
Xandra and Ken each bought two books at the sale.
- Xandra's books were priced at $2 and $15. How much less did she pay for the 2nd book than the 1st book?
- Ken paid a total of $50.30 for his two books. He paid $5.50 less for the 2nd book than for the 1st book. What was the price of the 1st book before discount?
|
1st book |
2nd book |
Total amount |
Original price
|
100% $15 |
100% $2 |
|
Discount |
- 10% |
- 20% |
|
Sale price |
90% |
80% |
? |
(a)
Selling price of the 1st book
= 90% x 15
=
90100 x 15
= $13.50
Selling price of 2nd book
= 80% x 2
=
80100 x 2
= $1.60
Amount that Xandra paid less for the 2nd book than the 1st book
= 13.50 - 1.60
= $11.90
|
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 + $5.50 |
1 u |
$50.30 |
(b)
Sale price of the 1st book = 1 u + 5.50
Sale price of the 2nd book = 1 u
Total amount that Ken paid
= 1 u + 5.50 + 1 u
= 2 u + 5.50
2 u + 5.50 = 50.30
2 u = 50.30 - 5.50
2 u = 44.80
1 u = 44.80 ÷ 2 = 22.40
Sale price of the 1st book
= 1 u + 5.50
= $27.90
90% of the price = $27.90
100% of the price =
27.9090 x 100 = $31
Selling price of the 1st book before discount = $31
Answer(s): (a) $11.90; (b) $31