Calculate and draw the marginal-revenue function associated

Question

Consider the demand function Q = 99 - p.

(a) At what output level does the elasticity equal -2 ?

(b) At what output level does the elasticity equal -1 ?

(c) Calculate and draw the marginal-revenue function associated with this demand.

(d) At what output level does the marginal revenue equal zero?

(e) Calculate the consumers surplus when p = 33 and p = 66.