Consider the Following Demand and Supply Curves $Q ^ { \mathrm { d } } = 100 - 2 \mathrm { P }$

Multiple Choice

Consider the following demand and supply curves: $Q ^ { \mathrm { d } } = 100 - 2 \mathrm { P }$ , and $Q ^ { s } = 1 / 2 P$ , calculate the equilibrium $P$ and $Q$ for this initial situation and assuming the demand curve changes to $Q ^ { d } = 100$ - P. Which of the following is correct?

A) The initial equilibrium is $P = 40 , Q = 20$ and the demand curve shifts left.
B) The initial equilibrium is $P = 40 , Q = 20$ and the new equilibrium is $P = 36 , Q = 28$ .
C) The initial equilibrium is $P = 40 , Q = 20$ and the new equilibrium is $P = 662 / 3$ and $Q = 331 / 3$ .
D) The initial equilibrium is $P = 40 , Q = 20$ and the demand curve shifts right.