Final answer:
The increased vacancy rate in an apartment complex, with all other factors being constant, would likely lead to a decrease in rental prices to attract more tenants and reach a new equilibrium. This answer is provided within the context of supply and demand without rent control influence.
Step-by-step explanation:
The question pertains to the effect of an increased vacancy rate in an apartment complex on rental prices, assuming all other factors are constant (ceteris paribus). In economics, the relationship between supply and demand determines price levels. When there is an excess supply of apartments (high vacancy rate), the price mechanism would suggest that rental prices would decrease to attract more tenants, thereby reaching a new equilibrium. This is particularly true in the absence of price controls such as rent control.
However, if the increase in the vacancy rate is due to factors such as a decrease in the quality of the apartments or a downturn in the neighborhood's desirability, landlords may not be able to attract more tenants even if they lower the rent. In the presence of rent control, the outcome could also differ because rents are not allowed to rise above a certain level, even if demand exceeds supply. The provided scenarios indicate that when demand shifts rightward, without rent control, prices tend to increase. However, if rent control is in place and demand still increases, a shortage occurs as the controlled rent leads to demand outstripping supply.