Selling what i bought in cash to finance 2 properties ?

[Khalid Akram]

I bought an apartment in 2012 for 350k in cash now im getting an offer of 500k  and i saved all the rental income of it, is it worth selling this one and finance other apartment and keep the extra cash in hand ? interest rate roughly between 2.5 to 3.5% no taxation on income or interest. 

Thanks