Fred is selling 700 textbooks. He sold 60% of them at $12 each, 60% of the remainder at a discount of 25% and the rest at cost price. He made a profit of $2484. Find the cost price of a textbook.

Price	$12	$9	Cost Price
Percent	60%	40%
		24%	16%
Number	420	168	Not needed
Amount collected	$5040	$1512	Not needed

Number of textbooks sold at $12
= 60% x 700
= ⁶⁰₁₀₀ x 700
= 420

Price after 25% discount
= 75% x 12
= ⁷⁵₁₀₀ x 12
= $9

Remaining textbooks
= 700 - 420
= 280

Number of textbooks sold at $9
= 60% x 280
= ⁶⁰₁₀₀ x 280
= 168

Number of textbooks sold at $12 or 25% discount
= 420 + 168
= 588

Total amount collected from the sale of 420 textbooks
= 420 x 12
= $5040

Total amount collected from the sale of the other 168 textbooks
= 168 x 9
= $1512

Total amount collected from the sale of textbooks sold at $12 or 25% discount
= 5040 + 1512
= $6552

Cost price of 588 textbooks
= 6552 - 2484
= $3528

Cost price of 1 textbook
= 3528 ÷ 588
= $6

Answer(s): $6