Answer:
Step-by-step explanation:
We are given the following in the question:
Quantity, q
Selling price in dollars per yard, p
Total revenue earned =
f(20)=13000
This means that 13000 yards of fabric is sold when the selling price is 20 dollars per yard.
f′(20)=−550
This means that increasing the selling price by 1 dollar per yards there is a decrease in fabric sales by 550.
We have to find R'(20)
Differentiating the above expression, we have,
Putting the values, we get,