Final answer:
This situation is an example of leveraging in real estate investment, where the investor purchased the property with a small down payment and financed the rest. After a year, they sold the property for a profit without increasing their initial investment.
Step-by-step explanation:
This situation is an example of leveraging in real estate investment. Leveraging involves using borrowed money, such as a mortgage, to increase the potential return on investment. In this case, the investor purchased the apartment building with a small down payment and financed the rest. After a year, the investor sold the property for a profit without increasing their initial investment. This strategy allows investors to maximize their returns by using other people's money.