A shopkeeper sold his first 50 textbooks at the price of $60 per book. After that, he sold the rest of his textbooks at $50 per book. If he collected a total of $25,000, how many textbooks did he sell?
A shopkeeper sold his first 50 textbooks at the price of $60 per book. After that, he sold the rest of his textbooks at $50 per book. If he collected a total of $25,000, how many textbooks did he sell?