Return on money for private money lenders

[Erin Butler]

This is a concept that confuses me, so I'll ask the community. 

Obviously- if you have private money on your side, that'll add rocket fuel to your  buisness. Here's my question, how does return on investment work for the private money lenders on buy and holds, whether it's single family or multifamily? 

Do you agree on the percentage return they recieve? Do you split the cashflow 50/50? Exactly how does this work for the private money lendors?