PSLE A book shop is having a book sale.
The 1st book is at 10% 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.
Sarah and Sam each bought two books at the sale.
- Sarah's books were priced at $16 and $31. How much less did she pay for the 2nd book than the 1st book?
- Sam paid a total of $31.50 for his two books. He paid $6.30 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% $31 |
100% $16 |
|
Discount |
- 10% |
- 30% |
|
Sale price |
90% |
70% |
? |
(a)
Selling price of the 1st book
= 90% x 31
=
90100 x 31
= $27.90
Selling price of 2nd book
= 70% x 16
=
70100 x 16
= $11.20
Amount that Sarah paid less for the 2nd book than the 1st book
= 27.90 - 11.20
= $16.70
|
1st book |
2nd book |
Total amount |
Original price |
100% |
100% |
|
Discount |
- 10% |
- 30% |
|
Sale price |
90%
|
70%
|
|
Compare 1st book and 2nd book |
1 u + $6.30 |
1 u |
$31.50 |
(b)
Sale price of the 1st book = 1 u + 6.30
Sale price of the 2nd book = 1 u
Total amount that Sam paid
= 1 u + 6.30 + 1 u
= 2 u + 6.30
2 u + 6.30 = 31.50
2 u = 31.50 - 6.30
2 u = 25.20
1 u = 25.20 ÷ 2 = 12.60
Sale price of the 1st book
= 1 u + 6.30
= $18.90
90% of the price = $18.90
100% of the price =
18.9090 x 100 = $21
Selling price of the 1st book before discount = $21
Answer(s): (a) $16.70; (b) $21