In the market for portable power banks, indicate whether the following events would cause an "increase or a decrease in demand" or an "increase or a decrease in the quantity demanded."

a. There is an increase in the price of carry cases for portable power banks. _
equilibrium quantity would , Equilibrium price would _.

b. There is a decrease in the price of devices used to charge portable power banks.
Equilibrium quantity would
Equilibrium price would

c. There is an increase in the number of consumers of portable power banks.
Equilibrium quantity would
Equilibrium price would

d. A booming economy increases the income of the typical buyer of portable power banks (this is a normal good).
Equilibrium quantity would
Equilibrium price would

e. Consumers of portable power banks anticipate that the price of this good will decline in the future.
Equilibrium quantity would
Equilibrium price would __

All the below demand changes are due to factors other than price, so are change (increase / decrease) in demand
Increase in Demand creates excess demand & competition among buyers increases prices, new equilibrium quantity. Decrease in demand creates excess supply & competition among sellers reduce price, new equilibrium quantity is less.

Carry cases for portable banks & devices used to charge portable power banks are complementary (jointly used goods with) portable power banks. Price & demand of complements are inversely related. So :-

a. Increase in carry cases price - Decreases Demand, Equilibrium price & quantity will fall

b. Decrease in charge devices - Increases Demand, Equilibrium price & quantity will rise

c. No. of Consumers increase - Increases Demand, Equilibrium price & quantity will rise

d. Income increase - Increases Demand, Equilibrium price & quantity will rise.

e. Price fall anticipated: Decreases Demand, Equilibrium price & quantity will fall