Glen is selling 800 guide books. He sold 60% of them at $10 each, 20% of the remainder at a discount of 20% and the rest at cost price. He made a profit of $2421. Find the cost price of a guide book.
| Price |
$10 |
$8 |
Cost Price |
| Percent |
60% |
40% |
| |
|
8% |
32% |
| Number |
480 |
64 |
Not needed |
| Amount collected |
$4800 |
$512 |
Not needed |
Number of guide books sold at $10
= 60% x 800
=
60100 x 800
= 480
Price after 20% discount
= 80% x 10
=
80100 x 10
= $8
Remaining guide books
= 800 - 480
= 320
Number of guide books sold at $8
= 20% x 320
=
20100 x 320
= 64
Number of guide books sold at $10 or 20% discount
= 480 + 64
= 544
Total amount collected from the sale of 480 guide books
= 480 x 10
= $4800
Total amount collected from the sale of the other 64 guide books
= 64 x 8
= $512
Total amount collected from the sale of guide books sold at $10 or 20% discount
= 4800 + 512
= $5312
Cost price of 544 guide books
= 5312 - 2421
= $1632
Cost price of 1 guide book
= 1632 ÷ 544
= $3
Answer(s): $3
