PSLE A shop is having a book sale.
The 1st book is at 5% 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.
Barbara and Andy each bought two books at the sale.
- Barbara's books were priced at $12 and $21. How much more did she pay for the 1st book than the 2nd book?
- Andy paid a total of $54.55 for his two books. He paid $8.15 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% $21 |
100% $12 |
|
Discount |
- 5% |
- 20% |
|
Sale price |
95% |
80% |
? |
(a)
Selling price of the 1st book
= 95% x 21
=
95100 x 21
= $19.95
Selling price of 2nd book
= 80% x 12
=
80100 x 12
= $9.60
Amount that Barbara paid more for the 1st book than the 2nd book
= 19.95 - 9.60
= $10.35
|
1st book |
2nd book |
Total amount |
Original price |
100% |
100% |
|
Discount |
- 5% |
- 20% |
|
Sale price |
95%
|
80%
|
|
Compare 1st book and 2nd book |
1 u + $8.15 |
1 u |
$54.55 |
(b)
Sale price of the 1st book = 1 u + 8.15
Sale price of the 2nd book = 1 u
Total amount that Andy paid
= 1 u + 8.15 + 1 u
= 2 u + 8.15
2 u + 8.15 = 54.55
2 u = 54.55 - 8.15
2 u = 46.40
1 u = 46.40 ÷ 2 = 23.20
Sale price of the 1st book
= 1 u + 8.15
= $31.35
95% of the price = $31.35
100% of the price =
31.3595 x 100 = $33
Selling price of the 1st book before discount = $33
Answer(s): (a) $10.35; (b) $33