PSLE A book shop is having a book sale.
The 1st book is at 5% discount.
The 2nd book is at 10% discount.
The price of the 2nd book should be equal or lower than the price of the 1st book.
Mary and Tim each bought two books at the sale.
- Mary's books were priced at $28 and $31. How much more did she pay for the 1st book than the 2nd book?
- Tim paid a total of $55.70 for his two books. He paid $8.90 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% $31 |
100% $28 |
|
Discount |
- 5% |
- 10% |
|
Sale price |
95% |
90% |
? |
(a)
Selling price of the 1st book
= 95% x 31
=
95100 x 31
= $29.45
Selling price of 2nd book
= 90% x 28
=
90100 x 28
= $25.20
Amount that Mary paid more for the 1st book than the 2nd book
= 29.45 - 25.20
= $4.25
|
1st book |
2nd book |
Total amount |
Original price |
100% |
100% |
|
Discount |
- 5% |
- 10% |
|
Sale price |
95%
|
90%
|
|
Compare 1st book and 2nd book |
1 u + $8.90 |
1 u |
$55.70 |
(b)
Sale price of the 1st book = 1 u + 8.90
Sale price of the 2nd book = 1 u
Total amount that Tim paid
= 1 u + 8.90 + 1 u
= 2 u + 8.90
2 u + 8.90 = 55.70
2 u = 55.70 - 8.90
2 u = 46.80
1 u = 46.80 ÷ 2 = 23.40
Sale price of the 1st book
= 1 u + 8.90
= $32.30
95% of the price = $32.30
100% of the price =
32.3095 x 100 = $34
Selling price of the 1st book before discount = $34
Answer(s): (a) $4.25; (b) $34