How is repaying Private investing possible.

[Dylan Nicks]

Hi I'm new to real estate and I just learned about private investing. While it seems like a quick way to fund projects, I do not understand how the loans can be paid off unless you are strictly flipping the house. 

For example, if you take a loan for $200K and it compounds at 18% per month, how could you ever generate enough cash flow to stop the runaway inflation from that loan?