Oliver is selling 900 colouring books. He sold 75% of them at $10 each, 20% of the remainder at a discount of 30% and the rest at cost price. He made a profit of $2435. Find the cost price of a colouring book.
| Price |
$10 |
$7 |
Cost Price |
| Percent |
75% |
25% |
| |
|
5% |
20% |
| Number |
675 |
45 |
Not needed |
| Amount collected |
$6750 |
$315 |
Not needed |
Number of colouring books sold at $10
= 75% x 900
=
75100 x 900
= 675
Price after 30% discount
= 70% x 10
=
70100 x 10
= $7
Remaining colouring books
= 900 - 675
= 225
Number of colouring books sold at $7
= 20% x 225
=
20100 x 225
= 45
Number of colouring books sold at $10 or 30% discount
= 675 + 45
= 720
Total amount collected from the sale of 675 colouring books
= 675 x 10
= $6750
Total amount collected from the sale of the other 45 colouring books
= 45 x 7
= $315
Total amount collected from the sale of colouring books sold at $10 or 30% discount
= 6750 + 315
= $7065
Cost price of 720 colouring books
= 7065 - 2435
= $5760
Cost price of 1 colouring book
= 5760 ÷ 720
= $8
Answer(s): $8
