How do you double check finances given?

[Nathan Visser]

Hi everyone,

New to everything, trying to secure my first deal, and after looking at the financials the property looks like a good cash-flow. 

The property is a newly renovated 3 story, 6-unit building and the numbers they have given me are

Annual revenue: 55,300 (including [potential] income from laundry [1,600])

Annual expenses: 15,300 

I know the 50% rule is just a general rule of thumb, but this seems unrealistic to me. Am I just being pessimistic and trying to find a reason not to do my first deal? or should I be somehow making sure these numbers are valid. I assume it's against the law to give out untrue numbers, but just wanted some feedback. 

Thanks in advance!