Rania is selling boxes of cookies door to door in her neighbourhood. At a price of $10 per box she sold 40 boxes per day. When the price was reduced to $4 per box she sold 100 boxes per day. Assuming that the demand conditions were unchanged, what is the price elasticity of demand for Rania's cookies?

At a price of $10 in the above figure, there is

A) a surplus of 200 units. B) a shortage of 200 units. C) a surplus of 400 units. D) a shortage of 400 units.

Management as it relates to home and family life was talked about for centuries but it became a formal study in the U.S. (and since worldwide) in the ____ century:

a. 17th b. 18th c. 19th d. 20th