The manager of a CD store has found that if the price of a CD is p(x)= 75-x/6 then x CDs will be sold. An expression for the total revenue from the sale of x CDs is R(x) =75x-x^2/6 How do you find the number of CDs that will produce maximum revenue?

1 Answer
Mar 10, 2018

225 CDs will produce the maximum revenue.

Explanation:

We know from Calculus that, for R_(max), we must have,

R'(x)=0, and, R''(x) lt 0.

Now, R(x)=75x-x^2/6 rArr R'(x)=75-1/6*2x=75-x/3.

:. R'(x)=0 rArr x/3=75, or, x=75*3=225.

Further, R'(x)=75-x/3 rArr R''(x)=-1/3 lt 0," already".

Hence, x=225" gives "R_(max).

Thus, 225 CDs will produce the maximum revenue R_max.

color(magenta)(BONUS :

R_max=R(225)=75*225-225^2/6=8437.5, and

"Price of a CD="p(225)=75-225/6=37.5.