Suppose that a wholesaler expects that his monthly revenue, in dollars, for an electronic game will be R(x) = 190x - 0

Answer:

a) option A

b) option A

Step-by-step explanation

we have   ?R = 190x−0.14x2?

marginal revenue is given by  ?M(x) = dxdR? = dxd?(190x−0.14x2) = 190−0.28x?

by definition it means the increase in revenue when an additional unit sold 

logic :  we have  ?R(x∗+dx) =R(x∗) + dxdR(x∗)? Δx?

so let   ?Δx = 1?

so ?R(x∗+1) = R(x∗) + dxdR(x∗)??

clearly ?dxdR(x∗)??  holds true with respect to definition 

now at ?x = 400 ?  ,  ?M(400) = 190−0.28×400 = 78?

since we have computed marginal revenue at ?x=400?  , so ?M(400)=78?  is the additional

revenue from ?x = 400+1?  i:e 401st unit , so option A is correct 

b) now at  ?x = 700 ?   ,  ?M(700) = 190−0.28×700 = −6?

since we have computed marginal revenue at ?x=700?  , so  ?M(700)=−6?  is the additional

revenue from ?x = 700+1?  i:e 701st unit  

note : since this negative which means a loss so option A is most appropriate