SOLUTION
From the question given, we are told that the demand D for bags, is inversely related to the price p. This is mathematically written as
If the proportionality sign is removed, a constant k will be introduced, and this becomes
(A) We are told that when the price per bag is $3.25, demand is 144 bags.
Hence D = 144 and p = 3.25, now let's find k using the equation above
Hence the equation that relates D to p is
(B) If the price is raised to $4.00 per bag, the theater will sell?
Using the relationship, this becomes
Hence the answer is 117 bags.