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.
Cathy and Cole each bought two books at the sale.
- Cathy's books were priced at $7 and $22. How much more did she pay for the 1st book than the 2nd book?
- Cole paid a total of $42.15 for his two books. He paid $6.45 more for the 1st book than for the 2nd book. What was the price of the 1st book before discount?
|
1st book |
2nd book |
Total amount |
Original price
|
100% $22 |
100% $7 |
|
Discount |
- 10% |
- 15% |
|
Sale price |
90% |
85% |
? |
(a)
Selling price of the 1st book
= 90% x 22
=
90100 x 22
= $19.80
Selling price of 2nd book
= 85% x 7
=
85100 x 7
= $5.95
Amount that Cathy paid more for the 1st book than the 2nd book
= 19.80 - 5.95
= $13.85
|
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 + $6.45 |
1 u |
$42.15 |
(b)
Sale price of the 1st book = 1 u + 6.45
Sale price of the 2nd book = 1 u
Total amount that Cole paid
= 1 u + 6.45 + 1 u
= 2 u + 6.45
2 u + 6.45 = 42.15
2 u = 42.15 - 6.45
2 u = 35.70
1 u = 35.70 ÷ 2 = 17.85
Sale price of the 1st book
= 1 u + 6.45
= $24.30
90% of the price = $24.30
100% of the price =
24.3090 x 100 = $27
Selling price of the 1st book before discount = $27
Answer(s): (a) $13.85; (b) $27