PSLE A stationery shop is having a book sale.
The 1st book is at 15% discount.
The 2nd book is at 30% discount.
The price of the 2nd book should be equal or lower than the price of the 1st book.
Lucy and Luis each bought two books at the sale.
- Lucy's books were priced at $19 and $21. How much more did she pay for the 1st book than the 2nd book?
- Luis paid a total of $41.75 for his two books. He paid $10.95 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% $19 |
|
Discount |
- 15% |
- 30% |
|
Sale price |
85% |
70% |
? |
(a)
Selling price of the 1st book
= 85% x 21
=
85100 x 21
= $17.85
Selling price of 2nd book
= 70% x 19
=
70100 x 19
= $13.30
Amount that Lucy paid more for the 1st book than the 2nd book
= 17.85 - 13.30
= $4.55
|
1st book |
2nd book |
Total amount |
Original price |
100% |
100% |
|
Discount |
- 15% |
- 30% |
|
Sale price |
85%
|
70%
|
|
Compare 1st book and 2nd book |
1 u + $10.95 |
1 u |
$41.75 |
(b)
Sale price of the 1st book = 1 u + 10.95
Sale price of the 2nd book = 1 u
Total amount that Luis paid
= 1 u + 10.95 + 1 u
= 2 u + 10.95
2 u + 10.95 = 41.75
2 u = 41.75 - 10.95
2 u = 30.80
1 u = 30.80 ÷ 2 = 15.40
Sale price of the 1st book
= 1 u + 10.95
= $26.35
85% of the price = $26.35
100% of the price =
26.3585 x 100 = $31
Selling price of the 1st book before discount = $31
Answer(s): (a) $4.55; (b) $31