mortgage_equivalence.rb

require "readline"

CURRENT_INTEREST_RATE=6.97/100

print "Input home value: "
value = gets.chomp.to_i

print "Input interest rate: "
rate = gets.chomp.to_f/100

i = (1+rate/12)**(12/12)-1
annuity = (1-(1/(1+i))**360)/i

payment = value/annuity

puts "\n$%.2f per month" % [payment]

current_i = (1+CURRENT_INTEREST_RATE/12)**(12/12)-1
current_annuity = (1-(1/(1+current_i))**360)/current_i
current_value = current_annuity * payment

puts "For a 30 year mortgage the equivalent house value at current rates is: $%.2f" % [current_value]