Suppose that the equation P=120-2Q_d describes the relationship between the price of a product and the quantity that consumers buy of that product.P is the price in dollars per unit and Q_d is the quantity consumers will buy in thousands of units.

Using a midpoint or arc elasticity calculation (that is, the method used by Khan in his videos), what is the price elasticity of demand for this product when price increases from $40 per pound to $50 per unit?

Group of answer choices

0.6

-0.6

-6

6