Use the Following General Linear Demand Relation to Answer Questions $$Q _ { d } = 680 - 9 P + 0.006 M - 4 P _ { R }$$

Multiple Choice

Use the following general linear demand relation to answer questions : $$Q _ { d } = 680 - 9 P + 0.006 M - 4 P _ { R }$$ where M is income and $P _ { R }$ is the price of a related good, R.
-If M = $15,000 and $P _ { R }$ = $20 and the supply function is $Q _ { s } = 30 + 3 P$ , equilibrium price and quantity are, respectively,

A) P = $55 and Q = 195.
B) P = $6 and Q = 38.
C) P = $12 and Q = 200.
D) P = $50 and Q = 170.
E) P = $40 and Q = 250.