Assuming that "elasticity" = P:
A.

- Elasticity = -0.889
B.

- The demand is inelastic because the elasticity > -1.
(C). Set P and Q to 1 in two separate functions. If Q < P revenue will increase. If Q > P revenue will decrease.

Q > P therefore revenue will decrease.
(D).

One obviously won't be able to maximize revenue if their price per unit, <em>P</em>, equals 0. Quantity of a product can only be sold in whole, so the closest integer to 90 is 89. The value of P that maximizes revenue is

- sqrt(10).
Therefore, the values of P and Q that maximize revenue are
3.162 and
89, respectively.