When the Local Used Bookstore Prices Economics Books at $15

Multiple Choice

When the local used bookstore prices economics books at $15 each,it generally sells 70 books per month.If it lowers the price to $7,sales increase to 90 books per month.Given this information,we know that the price elasticity of demand for economics books is about

A) 2.91, and an increase in price from $7 to $15 results in an increase in total revenue.
B) 2.91, and an increase in price from $7 to $15 results in a decrease in total revenue.
C) 0.34, and an increase in price from $7 to $15 results in an increase in total revenue.
D) 0.34, and an increase in price from $7 to $15 results in a decrease in total revenue.