PSLE A book shop is having a book sale.
The 1st book is at 10% discount.
The 2nd book is at 15% discount.
The price of the 2nd book should be equal or lower than the price of the 1st book.
Xuan and Luis each bought two books at the sale.
- Xuan's books were priced at $18 and $23. How much less did she pay for the 2nd book than the 1st book?
- Luis paid a total of $49.15 for his two books. He paid $6.65 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% $23 |
100% $18 |
|
Discount |
- 10% |
- 15% |
|
Sale price |
90% |
85% |
? |
(a)
Selling price of the 1st book
= 90% x 23
=
90100 x 23
= $20.70
Selling price of 2nd book
= 85% x 18
=
85100 x 18
= $15.30
Amount that Xuan paid less for the 2nd book than the 1st book
= 20.70 - 15.30
= $5.40
|
1st book |
2nd book |
Total amount |
Original price |
100% |
100% |
|
Discount |
- 10% |
- 15% |
|
Sale price |
90%
|
85%
|
|
Compare 1st book and 2nd book |
1 u + $6.65 |
1 u |
$49.15 |
(b)
Sale price of the 1st book = 1 u + 6.65
Sale price of the 2nd book = 1 u
Total amount that Luis paid
= 1 u + 6.65 + 1 u
= 2 u + 6.65
2 u + 6.65 = 49.15
2 u = 49.15 - 6.65
2 u = 42.50
1 u = 42.50 ÷ 2 = 21.25
Sale price of the 1st book
= 1 u + 6.65
= $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) $5.40; (b) $31