Question 322872
Condo price $ 90,000
15% down payment = 13500
Balance to be paid = 90000-14500=75500

The formula for monthly payment 
C=Po[r(1+r)^n / (1+r)^n-1]
Po=76500
r=9% ( 0.09/12)=0.0075
n=20 years = 240 months

..
(1+r)^n= (1+0.0075)^240=6.009
..
r(1+r)^n=0.0075*6.009=0.0450
..
(1+r)^n-1= 6.009-1= 5.009
..
r(1+r)^n/(1+r)^n-1 = 0.0450/5.009=0.00898
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Po*0.00989=76500*0.00989= 687.26 per month