Ketchup is a complement (as well as a condiment) for hot dogs
a. If the price of ketchup decreases, using a supply and demand diagrams for hot dogs, show what happens to equilibrium price, equilibrium quantity for hot dogs, and total revenue for producers of hot dogs.
b. Using supply/demand diagram, show what happens to consumer surplus, producer surplus and total surplus for hot dogs as a result of the decrease in the price of ketchup. [You can use the diagram in part (a) as well]