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,

4 quarts is equal to 1 gallon
Just multiply 26 by 4 and get 104
Answer:
Poundsis not equivalent to one of the metric units, that is WEIGHT.
You figure out the amount of chocolate doughnuts sold by multiplying 2/3 by 7 1/4
first you change 7 1/4 to an improper fraction:
7 1/4= 29/4
now multiply 2/3×29/4 by multiplying the two numerators then putting that over the two denominators multiplied: (2×29)/(3×4)=58/12
now simplify:58/12=4 10/12= 4 5/6
the answer is Stanley's doughnut shop sold
4 5/6 trays of chocolate doughnuts