Zeph is selling 1200 novels. He sold 60% of them at $10 each, 30% of the remainder at a discount of 30% and the rest at cost price. He made a profit of $2288. Find the cost price of a novel.

Price	$10	$7	Cost Price
Percent	60%	40%
		12%	28%
Number	720	144	Not needed
Amount collected	$7200	$1008	Not needed

Number of novels sold at $10
= 60% x 1200
= ⁶⁰₁₀₀ x 1200
= 720

Price after 30% discount
= 70% x 10
= ⁷⁰₁₀₀ x 10
= $7

Remaining novels
= 1200 - 720
= 480

Number of novels sold at $7
= 30% x 480
= ³⁰₁₀₀ x 480
= 144

Number of novels sold at $10 or 30% discount
= 720 + 144
= 864

Total amount collected from the sale of 720 novels
= 720 x 10
= $7200

Total amount collected from the sale of the other 144 novels
= 144 x 7
= $1008

Total amount collected from the sale of novels sold at $10 or 30% discount
= 7200 + 1008
= $8208

Cost price of 864 novels
= 8208 - 2288
= $9504

Cost price of 1 novel
= 9504 ÷ 864
= $11

Answer(s): $11