mortgage and per unit calculations

[Harvey Allen]

Hey guys, I was wondering so when Im doing calculations like the 50% rule and per unit calculations like when people say for a multi unit you should have about $100-200 per unit.

MY question you you guys are calculation this mortgage are you guys using a 30 amortize or 15 amortized. Cause I cant get these numbers to work for a 15 year.

or am i just not looking hard enough. :) 

thanks

p.s I love this site. I have been learning so much and been shown so much love especially since im so young