Japheth is selling 1200 colouring books. He sold 75% 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 $2263. Find the cost price of a colouring book.

Price	$12	$9	Cost Price
Percent	75%	25%
		15%	10%
Number	900	180	Not needed
Amount collected	$10800	$1620	Not needed

Number of colouring books sold at $12
= 75% x 1200
= ⁷⁵₁₀₀ x 1200
= 900

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

Remaining colouring books
= 1200 - 900
= 300

Number of colouring books sold at $9
= 60% x 300
= ⁶⁰₁₀₀ x 300
= 180

Number of colouring books sold at $12 or 25% discount
= 900 + 180
= 1080

Total amount collected from the sale of 900 colouring books
= 900 x 12
= $10800

Total amount collected from the sale of the other 180 colouring books
= 180 x 9
= $1620

Total amount collected from the sale of colouring books sold at $12 or 25% discount
= 10800 + 1620
= $12420

Cost price of 1080 colouring books
= 12420 - 2263
= $6480

Cost price of 1 colouring book
= 6480 ÷ 1080
= $6

Answer(s): $6