1
2
3
4
5
6
7

cap_growth = 5
v += (@property.current_value / 100 * cap_growth)

for i in (0..7)
  puts v
  v +=  v / 100 * cap_growth
end

1
2
3
4
5
6
7

cap_growth = 5

v = @property.current_value

8.times do
  puts v += v/ 100 * cap_growth
end

1

a = (0..8).inject([]) {|a, i| a << (v += (v/100) * cap_growth)}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24

#!/usr/bin/ruby -w
#
#  Using geometric series to calculate value of:
#   ar^n + ar^(n-1) + ... + ar^2 + ar + a 
#   
#   = a(1-r^(n+1))/(1-r)
#
#  also adding a starting savings to get:
# 
#  a(1-r^(n+1))/(1-r) + sr^n
#

puts "Enter Starting Amount"
s = gets.chomp.to_f
puts "Enter savings per year"
a = gets.chomp.to_f
puts "Enter savings rate of return"
r = gets.chomp.to_f
puts "Enter number of years"
n = gets.chomp.to_f

value = a*(1-r**(n+1))/(1-r) + s*r**n
value = (value*100).round / 100.0
puts "Saved: $#{value} in #{n} years"

1
2
3
4
5
6
7
8
9
10
11
12
13
14

class Investment < Struct.new(:start_year, :start_value, :interest_rate)

  def value_at(year)
    start_value * (1 + interest_rate) ** (year - start_year)
  end

end

# # Sample usage
# we invest 100 in 1990 at 5% interest and want to know the value per
# every year from 1990 to 2005

i = Investment.new(1990, 100, 0.05)
(1990..2005).each { |year| puts i.value_at(year) }