When a university bookstore prices chemistry textbooks at $200 each, it generally sells 120 books per month. If it lowers the price to $160, sales increase to 160 books per month. Given this information, we know that the price elasticity of demand for chemistry books is about. a. 1.29, and a decrease in price from $200 to $160 results in an increase in total revenue. b. 1.29, and a decrease in price from $200 to $160 results in a decrease in total revenue. c. 0.78, and a decrease in price from $200 to $160 results in an increase in total revenue. d. 0.78, and a decrease in price from $200 to $160 results in a decrease in total revenue.