Use the equity or put 20% down

[Bridget C Creighton]

I'm just getting started and trying to determine the smartest way to scale up quickly.  I have a offer submitted on my first rental property, which is a duplex. I'm planning to pay cash, turn around and finance it, and use the cash again to purchase the next property. Any recommendations on letting the equity work and keeping my cash instead of putting 20% down when I do refinance?