Billy is selling 600 non-fiction books. He sold 50% of them at $8 each, 60% of the remainder at a discount of 25% and the rest at cost price. He made a profit of $2089. Find the cost price of a non-fiction book.
| Price |
$8 |
$6 |
Cost Price |
| Percent |
50% |
50% |
| |
|
30% |
20% |
| Number |
300 |
180 |
Not needed |
| Amount collected |
$2400 |
$1080 |
Not needed |
Number of non-fiction books sold at $8
= 50% x 600
=
50100 x 600
= 300
Price after 25% discount
= 75% x 8
=
75100 x 8
= $6
Remaining non-fiction books
= 600 - 300
= 300
Number of non-fiction books sold at $6
= 60% x 300
=
60100 x 300
= 180
Number of non-fiction books sold at $8 or 25% discount
= 300 + 180
= 480
Total amount collected from the sale of 300 non-fiction books
= 300 x 8
= $2400
Total amount collected from the sale of the other 180 non-fiction books
= 180 x 6
= $1080
Total amount collected from the sale of non-fiction books sold at $8 or 25% discount
= 2400 + 1080
= $3480
Cost price of 480 non-fiction books
= 3480 - 2089
= $5280
Cost price of 1 non-fiction book
= 5280 ÷ 480
= $11
Answer(s): $11
