Suppose That the Market for Cigarettes Is Initially in Equilibrium $P = 60 - Q ^ { d }$

Multiple Choice

Suppose that the market for cigarettes is initially in equilibrium and is perfectly competitive. The demand curve can be expressed as $P = 60 - Q ^ { d }$ ; the supply curve can be expressed as $P =$ $0.5 Q ^ { s }$ . Quantity is expressed in millions of boxes per month. What are the amount traded and the price for this market?

A) $Q = 40 ; P = 20$
B) $Q = 20 ; P = 40$
C) $Q = 30 ; P = 30$
D) $Q = 30 ; P = 15$