PSLE A shop is having a book sale.
The 1st book is at 25% 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.
Erika and Mark each bought two books at the sale.
- Erika's books were priced at $9 and $15. How much more did she pay for the 1st book than the 2nd book?
- Mark paid a total of $27.45 for his two books. He paid $7.05 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% $9 |
|
Discount |
- 25% |
- 40% |
|
Sale price |
75% |
60% |
? |
(a)
Selling price of the 1st book
= 75% x 15
=
75100 x 15
= $11.25
Selling price of 2nd book
= 60% x 9
=
60100 x 9
= $5.40
Amount that Erika paid more for the 1st book than the 2nd book
= 11.25 - 5.40
= $5.85
|
1st book |
2nd book |
Total amount |
Original price |
100% |
100% |
|
Discount |
- 25% |
- 40% |
|
Sale price |
75%
|
60%
|
|
Compare 1st book and 2nd book |
1 u + $7.05 |
1 u |
$27.45 |
(b)
Sale price of the 1st book = 1 u + 7.05
Sale price of the 2nd book = 1 u
Total amount that Mark paid
= 1 u + 7.05 + 1 u
= 2 u + 7.05
2 u + 7.05 = 27.45
2 u = 27.45 - 7.05
2 u = 20.40
1 u = 20.40 ÷ 2 = 10.20
Sale price of the 1st book
= 1 u + 7.05
= $17.25
75% of the price = $17.25
100% of the price =
17.2575 x 100 = $23
Selling price of the 1st book before discount = $23
Answer(s): (a) $5.85; (b) $23