David is selling 700 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 $2249. Find the cost price of a colouring book.
| Price |
$10 |
$7 |
Cost Price |
| Percent |
75% |
25% |
| |
|
5% |
20% |
| Number |
525 |
35 |
Not needed |
| Amount collected |
$5250 |
$245 |
Not needed |
Number of colouring books sold at $10
= 75% x 700
=
75100 x 700
= 525
Price after 30% discount
= 70% x 10
=
70100 x 10
= $7
Remaining colouring books
= 700 - 525
= 175
Number of colouring books sold at $7
= 20% x 175
=
20100 x 175
= 35
Number of colouring books sold at $10 or 30% discount
= 525 + 35
= 560
Total amount collected from the sale of 525 colouring books
= 525 x 10
= $5250
Total amount collected from the sale of the other 35 colouring books
= 35 x 7
= $245
Total amount collected from the sale of colouring books sold at $10 or 30% discount
= 5250 + 245
= $5495
Cost price of 560 colouring books
= 5495 - 2249
= $5040
Cost price of 1 colouring book
= 5040 ÷ 560
= $9
Answer(s): $9
