The shop bought a batch of math exercise books, one in 5 yuan at the wholesale price1.and one in 2 yuan at the retail price. Retail 240 copies earned 45 yuan. How many copies of homework do you buy?
The profit per book is 2.0- 1.5 =0.5.
The profit of 240 books is 240 * (2.0-1.5) =120.
So the remaining (120-45 )/ 1.5=50 copies.
So a * * * purchase job is 50+240 =290.