Rent (24% return) or sell ( 75% gain )?

[Wendy BK]

Hi,

I recently purchased a investment property and originally planned to rent out, which is why I used a mortgage instead of cash. If i sell it, I may make about 20k (rate of return is about 75%). And I can rent it for cash flow of around $5000 a year (around 24% return). The reason I am thinking to sell is so that I can buy another property with a mortgage ( lenders are not willing to give more than 4 mortgages for investment properties).

What's your advice? Thanks a lot!

Wendy