quantizor

Total qualified mortgage amount = ( 0.5 - c(m/(1-(1+m)^-n)) - T(c) - I(c) + R((A-d*12)/12) ) / ( m/(1-(1+m)^-n) + T + I )

A = gross annual income
I = decimal insurance rate
R = decimal maximum allowed payment/income ratio based on creditworthiness (44% -> 0.44, etc.)
T = decimal tax rate / 12

c = down payment
d = gross monthly debt
i = decimal interest rate

gist:10295917

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