PSLE A store is having a book sale. The 1st book is at 20% 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.
- Kathy's books were priced at $17 and $22. How much less did she pay for the 2nd book than the 1st book?
- Daniel paid a total of $41.60 for his two books. He paid $12.80 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% $22 |
100% $17 |
|
Discount |
- 20% |
- 40% |
|
Sale price |
80% |
60% |
? |
(a)
Selling price of the 1st book
= 80% x 22
=
80100 x 22
= $17.60
Selling price of 2nd book
= 60% x 17
=
60100 x 17
= $10.20
Amount that Kathy paid less for the 2nd book than the 1st book
= 17.60 - 10.20
= $7.40
|
1st book |
2nd book |
Total amount |
Original price |
100% |
100% |
|
Discount |
- 20% |
- 40% |
|
Sale price |
80%
|
60%
|
|
Compare 1st book and 2nd book |
1 u + $12.80 |
1 u |
$41.60 |
(b)
Sale price of the 1st book = 1 u + 12.80
Sale price of the 2nd book = 1 u
Total amount that Daniel paid
= 1 u + 12.80 + 1 u
= 2 u + 12.80
2 u + 12.80 = 41.60
2 u = 41.60 - 12.80
2 u = 28.80
1 u = 28.80 ÷ 2 = 14.40
Sale price of the 1st book
= 1 u + 12.80
= $27.20
80% of the price = $27.20
100% of the price =
27.2080 x 100 = $34
Selling price of the 1st book before discount = $34
Answer(s): (a) $7.40; (b) $34