Oliver is selling 600 non-fiction books. He sold 50% of them at $8 each, 40% of the remainder at a discount of 25% and the rest at cost price. He made a profit of $2320. Find the cost price of a non-fiction book.
| Price |
$8 |
$6 |
Cost Price |
| Percent |
50% |
50% |
| |
|
20% |
30% |
| Number |
300 |
120 |
Not needed |
| Amount collected |
$2400 |
$720 |
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
= 40% x 300
=
40100 x 300
= 120
Number of non-fiction books sold at $8 or 25% discount
= 300 + 120
= 420
Total amount collected from the sale of 300 non-fiction books
= 300 x 8
= $2400
Total amount collected from the sale of the other 120 non-fiction books
= 120 x 6
= $720
Total amount collected from the sale of non-fiction books sold at $8 or 25% discount
= 2400 + 720
= $3120
Cost price of 420 non-fiction books
= 3120 - 2320
= $4620
Cost price of 1 non-fiction book
= 4620 ÷ 420
= $11
Answer(s): $11
